diff --git a/browser/components/newtab/content-src/asrouter/templates/StartupOverlay/StartupOverlay.jsx b/browser/components/newtab/content-src/asrouter/templates/StartupOverlay/StartupOverlay.jsx
index 11d2e91db309..87129fa4bbb5 100644
--- a/browser/components/newtab/content-src/asrouter/templates/StartupOverlay/StartupOverlay.jsx
+++ b/browser/components/newtab/content-src/asrouter/templates/StartupOverlay/StartupOverlay.jsx
@@ -18,6 +18,7 @@ export class _StartupOverlay extends React.PureComponent {
     this.state = {
       emailInput: "",
       overlayRemoved: false,
+      deviceId: "",
       flowId: "",
       flowBeginTime: 0,
     };
@@ -31,8 +32,8 @@ export class _StartupOverlay extends React.PureComponent {
         const fxaParams = "entrypoint=activity-stream-firstrun&form_type=email";
         const response = await fetch(`${this.props.fxa_endpoint}/metrics-flow?${fxaParams}&${this.utmParams}`, {credentials: "omit"});
         if (response.status === 200) {
-          const {flowId, flowBeginTime} = await response.json();
-          this.setState({flowId, flowBeginTime});
+          const {deviceId, flowId, flowBeginTime} = await response.json();
+          this.setState({deviceId, flowId, flowBeginTime});
         } else {
           this.props.dispatch(ac.OnlyToMain({type: at.TELEMETRY_UNDESIRED_EVENT, data: {event: "FXA_METRICS_FETCH_ERROR", value: response.status}}));
         }
@@ -132,6 +133,7 @@ export class _StartupOverlay extends React.PureComponent {
                 <input name="utm_campaign" type="hidden" value="firstrun" />
                 <input name="utm_medium" type="hidden" value="referral" />
                 <input name="utm_term" type="hidden" value="trailhead-control" />
+                <input name="device_id" type="hidden" value={this.state.deviceId} />
                 <input name="flow_id" type="hidden" value={this.state.flowId} />
                 <input name="flow_begin_time" type="hidden" value={this.state.flowBeginTime} />
                 <span className="error">{this.props.intl.formatMessage({id: "firstrun_invalid_input"})}</span>
diff --git a/browser/components/newtab/content-src/asrouter/templates/Trailhead/Trailhead.jsx b/browser/components/newtab/content-src/asrouter/templates/Trailhead/Trailhead.jsx
index 211c42a1fe77..1ed643b8a659 100644
--- a/browser/components/newtab/content-src/asrouter/templates/Trailhead/Trailhead.jsx
+++ b/browser/components/newtab/content-src/asrouter/templates/Trailhead/Trailhead.jsx
@@ -38,10 +38,12 @@ export class _Trailhead extends React.PureComponent {
       isModalOpen: true,
       showCardPanel: true,
       showCards: false,
+      // The params below are for FxA metrics
+      deviceId: "",
       flowId: "",
       flowBeginTime: 0,
     };
-    this.didFetch = false;
+    this.fxaMetricsInitialized = false;
   }
 
   get dialog() {
@@ -55,15 +57,15 @@ export class _Trailhead extends React.PureComponent {
       link.rel = "localization";
     });
 
-    if (this.props.fxaEndpoint && !this.didFetch) {
+    if (this.props.fxaEndpoint && !this.fxaMetricsInitialized) {
       try {
-        this.didFetch = true;
+        this.fxaMetricsInitialized = true;
         const url = new URL(`${this.props.fxaEndpoint}/metrics-flow?entrypoint=activity-stream-firstrun&form_type=email`);
         this.addUtmParams(url);
         const response = await fetch(url, {credentials: "omit"});
         if (response.status === 200) {
-          const {flowId, flowBeginTime} = await response.json();
-          this.setState({flowId, flowBeginTime});
+          const {deviceId, flowId, flowBeginTime} = await response.json();
+          this.setState({deviceId, flowId, flowBeginTime});
         } else {
           this.props.dispatch(ac.OnlyToMain({type: at.TELEMETRY_UNDESIRED_EVENT, data: {event: "FXA_METRICS_FETCH_ERROR", value: response.status}}));
         }
@@ -194,6 +196,7 @@ export class _Trailhead extends React.PureComponent {
       this.addUtmParams(url, true);
 
       if (action.addFlowParams) {
+        url.searchParams.append("device_id", this.state.deviceId);
         url.searchParams.append("flow_id", this.state.flowId);
         url.searchParams.append("flow_begin_time", this.state.flowBeginTime);
       }
@@ -232,9 +235,9 @@ export class _Trailhead extends React.PureComponent {
             {this.getStringValue(content.learn.text)}
           </a>
         </div>
-        <div className="trailheadForm">
-          <h3 data-l10n-id={content.form.title.string_id}>{this.getStringValue(content.form.title)}</h3>
-          <p data-l10n-id={content.form.text.string_id}>{this.getStringValue(content.form.text)}</p>
+        <div role="group" aria-labelledby="joinFormHeader" aria-describedby="joinFormBody" className="trailheadForm">
+          <h3 id="joinFormHeader" data-l10n-id={content.form.title.string_id}>{this.getStringValue(content.form.title)}</h3>
+          <p id="joinFormBody" data-l10n-id={content.form.text.string_id}>{this.getStringValue(content.form.text)}</p>
           <form method="get" action={this.props.fxaEndpoint} target="_blank" rel="noopener noreferrer" onSubmit={this.onSubmit}>
             <input name="service" type="hidden" value="sync" />
             <input name="action" type="hidden" value="email" />
@@ -243,6 +246,7 @@ export class _Trailhead extends React.PureComponent {
             <input name="utm_source" type="hidden" value="activity-stream" />
             <input name="utm_campaign" type="hidden" value="firstrun" />
             <input name="utm_term" type="hidden" value={utm_term} />
+            <input name="device_id" type="hidden" value={this.state.deviceId} />
             <input name="flow_id" type="hidden" value={this.state.flowId} />
             <input name="flow_begin_time" type="hidden" value={this.state.flowBeginTime} />
             <input name="style" type="hidden" value="trailhead" />
diff --git a/browser/components/newtab/content-src/asrouter/templates/Trailhead/_Trailhead.scss b/browser/components/newtab/content-src/asrouter/templates/Trailhead/_Trailhead.scss
index bc3dd42f777c..ca713f0ff77f 100644
--- a/browser/components/newtab/content-src/asrouter/templates/Trailhead/_Trailhead.scss
+++ b/browser/components/newtab/content-src/asrouter/templates/Trailhead/_Trailhead.scss
@@ -402,7 +402,7 @@
 
 .inline-onboarding {
   &.activity-stream.welcome {
-    overflow: scroll;
+    overflow-y: scroll;
   }
 
   .modalOverlayInner {
diff --git a/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.jsx b/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.jsx
index 42044efdd982..0204076fa35a 100644
--- a/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.jsx
+++ b/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.jsx
@@ -78,10 +78,15 @@ export class DSImage extends React.PureComponent {
             this.state.containerHeight * 2
           );
 
-          img = (<img onError={this.onOptimizedImageError} src={source} srcSet={`${source2x} 2x`} />);
+          img = (<img crossOrigin="anonymous"
+            onError={this.onOptimizedImageError}
+            src={source}
+            srcSet={`${source2x} 2x`} />);
         }
       } else if (!this.state.nonOptimizedImageFailed) {
-        img = (<img onError={this.onNonOptimizedImageError} src={this.props.source} />);
+        img = (<img crossOrigin="anonymous"
+          onError={this.onNonOptimizedImageError}
+          src={this.props.source} />);
       } else {
         // Remove the img element if both sources fail. Render a placeholder instead.
         img = (<div className="broken-image" />);
diff --git a/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.scss b/browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/_DSImage.scss
similarity index 100%
rename from browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/DSImage.scss
rename to browser/components/newtab/content-src/components/DiscoveryStreamComponents/DSImage/_DSImage.scss
diff --git a/browser/components/newtab/content-src/styles/_mixins.scss b/browser/components/newtab/content-src/styles/_mixins.scss
index e63b61c8c7f5..a206fadb597b 100644
--- a/browser/components/newtab/content-src/styles/_mixins.scss
+++ b/browser/components/newtab/content-src/styles/_mixins.scss
@@ -10,7 +10,10 @@
 
 // Note: lineHeight and fontSize should be unitless but can be derived from pixel values
 @mixin limit-visibile-lines($line-count, $line-height, $font-size) {
+  -webkit-box-orient: vertical;
+  display: -webkit-box;
   font-size: $font-size * 1px;
+  -webkit-line-clamp: $line-count;
   line-height: $line-height * 1px;
   max-height: 1em * $line-count * $line-height / $font-size;
   overflow: hidden;
diff --git a/browser/components/newtab/css/activity-stream-linux.css b/browser/components/newtab/css/activity-stream-linux.css
index 002aaef4cbfd..0dc3a6224312 100644
--- a/browser/components/newtab/css/activity-stream-linux.css
+++ b/browser/components/newtab/css/activity-stream-linux.css
@@ -1946,7 +1946,10 @@ main {
     .ds-column-10 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-11 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-12 .ds-card-grid.ds-card-grid-divisible-by-4 .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 15px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4em;
       overflow: hidden; }
@@ -1961,7 +1964,10 @@ main {
     line-height: 1.538;
     margin: 8px 0; }
   .ds-hero .excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden;
@@ -2030,7 +2036,10 @@ main {
       flex-direction: column;
       justify-content: space-between; }
       .ds-hero .wrapper .meta header {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 22px;
+        -webkit-line-clamp: 4;
         line-height: 28px;
         max-height: 5.09091em;
         overflow: hidden;
@@ -2150,7 +2159,10 @@ main {
         .ds-column-10 .ds-hero .wrapper .meta header,
         .ds-column-11 .ds-hero .wrapper .meta header,
         .ds-column-12 .ds-hero .wrapper .meta header {
+          -webkit-box-orient: vertical;
+          display: -webkit-box;
           font-size: 22px;
+          -webkit-line-clamp: 3;
           line-height: 28px;
           max-height: 3.81818em;
           overflow: hidden; }
@@ -2186,7 +2198,10 @@ main {
       .ds-column-10 .ds-hero .cards .ds-card .title,
       .ds-column-11 .ds-hero .cards .ds-card .title,
       .ds-column-12 .ds-hero .cards .ds-card .title {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 14px;
+        -webkit-line-clamp: 3;
         line-height: 20px;
         max-height: 4.28571em;
         overflow: hidden; }
@@ -2215,7 +2230,10 @@ main {
     line-height: 20px;
     position: relative; }
   .ds-list:not(.ds-list-full-width) .ds-list-item-title {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden; }
@@ -2329,7 +2347,10 @@ main {
   position: relative; }
 
 .ds-list-full-width .ds-list-item-title {
+  -webkit-box-orient: vertical;
+  display: -webkit-box;
   font-size: 17px;
+  -webkit-line-clamp: 3;
   line-height: 24px;
   max-height: 4.23529em;
   overflow: hidden; }
@@ -2356,7 +2377,10 @@ main {
     justify-content: space-between;
     height: 100%; }
   .ds-list-item .ds-list-item-excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 2;
     line-height: 20px;
     max-height: 2.85714em;
     overflow: hidden;
@@ -2368,7 +2392,10 @@ main {
     margin: 0; }
   .ds-list-item .ds-list-item-info,
   .ds-list-item .ds-list-item-context {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 1;
     line-height: 20px;
     max-height: 1.42857em;
     overflow: hidden;
@@ -2636,13 +2663,19 @@ main {
       flex-grow: 1;
       margin: 0 0 12px; }
     .ds-card .meta .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 17px;
+      -webkit-line-clamp: 3;
       line-height: 24px;
       max-height: 4.23529em;
       overflow: hidden;
       font-weight: 600; }
     .ds-card .meta .excerpt {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 14px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4.28571em;
       overflow: hidden; }
@@ -3976,7 +4009,7 @@ a.firstrun-link {
     text-align: center; }
 
 .inline-onboarding.activity-stream.welcome {
-  overflow: scroll; }
+  overflow-y: scroll; }
 
 .inline-onboarding .modalOverlayInner {
   position: absolute; }
diff --git a/browser/components/newtab/css/activity-stream-mac.css b/browser/components/newtab/css/activity-stream-mac.css
index f54e5c263236..23bd56df449c 100644
--- a/browser/components/newtab/css/activity-stream-mac.css
+++ b/browser/components/newtab/css/activity-stream-mac.css
@@ -1949,7 +1949,10 @@ main {
     .ds-column-10 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-11 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-12 .ds-card-grid.ds-card-grid-divisible-by-4 .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 15px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4em;
       overflow: hidden; }
@@ -1964,7 +1967,10 @@ main {
     line-height: 1.538;
     margin: 8px 0; }
   .ds-hero .excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden;
@@ -2033,7 +2039,10 @@ main {
       flex-direction: column;
       justify-content: space-between; }
       .ds-hero .wrapper .meta header {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 22px;
+        -webkit-line-clamp: 4;
         line-height: 28px;
         max-height: 5.09091em;
         overflow: hidden;
@@ -2153,7 +2162,10 @@ main {
         .ds-column-10 .ds-hero .wrapper .meta header,
         .ds-column-11 .ds-hero .wrapper .meta header,
         .ds-column-12 .ds-hero .wrapper .meta header {
+          -webkit-box-orient: vertical;
+          display: -webkit-box;
           font-size: 22px;
+          -webkit-line-clamp: 3;
           line-height: 28px;
           max-height: 3.81818em;
           overflow: hidden; }
@@ -2189,7 +2201,10 @@ main {
       .ds-column-10 .ds-hero .cards .ds-card .title,
       .ds-column-11 .ds-hero .cards .ds-card .title,
       .ds-column-12 .ds-hero .cards .ds-card .title {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 14px;
+        -webkit-line-clamp: 3;
         line-height: 20px;
         max-height: 4.28571em;
         overflow: hidden; }
@@ -2218,7 +2233,10 @@ main {
     line-height: 20px;
     position: relative; }
   .ds-list:not(.ds-list-full-width) .ds-list-item-title {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden; }
@@ -2332,7 +2350,10 @@ main {
   position: relative; }
 
 .ds-list-full-width .ds-list-item-title {
+  -webkit-box-orient: vertical;
+  display: -webkit-box;
   font-size: 17px;
+  -webkit-line-clamp: 3;
   line-height: 24px;
   max-height: 4.23529em;
   overflow: hidden; }
@@ -2359,7 +2380,10 @@ main {
     justify-content: space-between;
     height: 100%; }
   .ds-list-item .ds-list-item-excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 2;
     line-height: 20px;
     max-height: 2.85714em;
     overflow: hidden;
@@ -2371,7 +2395,10 @@ main {
     margin: 0; }
   .ds-list-item .ds-list-item-info,
   .ds-list-item .ds-list-item-context {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 1;
     line-height: 20px;
     max-height: 1.42857em;
     overflow: hidden;
@@ -2639,13 +2666,19 @@ main {
       flex-grow: 1;
       margin: 0 0 12px; }
     .ds-card .meta .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 17px;
+      -webkit-line-clamp: 3;
       line-height: 24px;
       max-height: 4.23529em;
       overflow: hidden;
       font-weight: 600; }
     .ds-card .meta .excerpt {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 14px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4.28571em;
       overflow: hidden; }
@@ -3979,7 +4012,7 @@ a.firstrun-link {
     text-align: center; }
 
 .inline-onboarding.activity-stream.welcome {
-  overflow: scroll; }
+  overflow-y: scroll; }
 
 .inline-onboarding .modalOverlayInner {
   position: absolute; }
diff --git a/browser/components/newtab/css/activity-stream-windows.css b/browser/components/newtab/css/activity-stream-windows.css
index 2ab228ee77d2..469efa7db41b 100644
--- a/browser/components/newtab/css/activity-stream-windows.css
+++ b/browser/components/newtab/css/activity-stream-windows.css
@@ -1946,7 +1946,10 @@ main {
     .ds-column-10 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-11 .ds-card-grid.ds-card-grid-divisible-by-4 .title,
     .ds-column-12 .ds-card-grid.ds-card-grid-divisible-by-4 .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 15px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4em;
       overflow: hidden; }
@@ -1961,7 +1964,10 @@ main {
     line-height: 1.538;
     margin: 8px 0; }
   .ds-hero .excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden;
@@ -2030,7 +2036,10 @@ main {
       flex-direction: column;
       justify-content: space-between; }
       .ds-hero .wrapper .meta header {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 22px;
+        -webkit-line-clamp: 4;
         line-height: 28px;
         max-height: 5.09091em;
         overflow: hidden;
@@ -2150,7 +2159,10 @@ main {
         .ds-column-10 .ds-hero .wrapper .meta header,
         .ds-column-11 .ds-hero .wrapper .meta header,
         .ds-column-12 .ds-hero .wrapper .meta header {
+          -webkit-box-orient: vertical;
+          display: -webkit-box;
           font-size: 22px;
+          -webkit-line-clamp: 3;
           line-height: 28px;
           max-height: 3.81818em;
           overflow: hidden; }
@@ -2186,7 +2198,10 @@ main {
       .ds-column-10 .ds-hero .cards .ds-card .title,
       .ds-column-11 .ds-hero .cards .ds-card .title,
       .ds-column-12 .ds-hero .cards .ds-card .title {
+        -webkit-box-orient: vertical;
+        display: -webkit-box;
         font-size: 14px;
+        -webkit-line-clamp: 3;
         line-height: 20px;
         max-height: 4.28571em;
         overflow: hidden; }
@@ -2215,7 +2230,10 @@ main {
     line-height: 20px;
     position: relative; }
   .ds-list:not(.ds-list-full-width) .ds-list-item-title {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 3;
     line-height: 20px;
     max-height: 4.28571em;
     overflow: hidden; }
@@ -2329,7 +2347,10 @@ main {
   position: relative; }
 
 .ds-list-full-width .ds-list-item-title {
+  -webkit-box-orient: vertical;
+  display: -webkit-box;
   font-size: 17px;
+  -webkit-line-clamp: 3;
   line-height: 24px;
   max-height: 4.23529em;
   overflow: hidden; }
@@ -2356,7 +2377,10 @@ main {
     justify-content: space-between;
     height: 100%; }
   .ds-list-item .ds-list-item-excerpt {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 2;
     line-height: 20px;
     max-height: 2.85714em;
     overflow: hidden;
@@ -2368,7 +2392,10 @@ main {
     margin: 0; }
   .ds-list-item .ds-list-item-info,
   .ds-list-item .ds-list-item-context {
+    -webkit-box-orient: vertical;
+    display: -webkit-box;
     font-size: 14px;
+    -webkit-line-clamp: 1;
     line-height: 20px;
     max-height: 1.42857em;
     overflow: hidden;
@@ -2636,13 +2663,19 @@ main {
       flex-grow: 1;
       margin: 0 0 12px; }
     .ds-card .meta .title {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 17px;
+      -webkit-line-clamp: 3;
       line-height: 24px;
       max-height: 4.23529em;
       overflow: hidden;
       font-weight: 600; }
     .ds-card .meta .excerpt {
+      -webkit-box-orient: vertical;
+      display: -webkit-box;
       font-size: 14px;
+      -webkit-line-clamp: 3;
       line-height: 20px;
       max-height: 4.28571em;
       overflow: hidden; }
@@ -3976,7 +4009,7 @@ a.firstrun-link {
     text-align: center; }
 
 .inline-onboarding.activity-stream.welcome {
-  overflow: scroll; }
+  overflow-y: scroll; }
 
 .inline-onboarding .modalOverlayInner {
   position: absolute; }
diff --git a/browser/components/newtab/data/content/activity-stream.bundle.js b/browser/components/newtab/data/content/activity-stream.bundle.js
index ba2b9f1ed96c..8faf1c008d1a 100644
--- a/browser/components/newtab/data/content/activity-stream.bundle.js
+++ b/browser/components/newtab/data/content/activity-stream.bundle.js
@@ -2996,6 +2996,7 @@ class _StartupOverlay extends react__WEBPACK_IMPORTED_MODULE_3___default.a.PureC
     this.state = {
       emailInput: "",
       overlayRemoved: false,
+      deviceId: "",
       flowId: "",
       flowBeginTime: 0
     };
@@ -3013,10 +3014,12 @@ class _StartupOverlay extends react__WEBPACK_IMPORTED_MODULE_3___default.a.PureC
 
         if (response.status === 200) {
           const {
+            deviceId,
             flowId,
             flowBeginTime
           } = await response.json();
           this.setState({
+            deviceId,
             flowId,
             flowBeginTime
           });
@@ -3212,6 +3215,10 @@ class _StartupOverlay extends react__WEBPACK_IMPORTED_MODULE_3___default.a.PureC
       name: "utm_term",
       type: "hidden",
       value: "trailhead-control"
+    }), react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("input", {
+      name: "device_id",
+      type: "hidden",
+      value: this.state.deviceId
     }), react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("input", {
       name: "flow_id",
       type: "hidden",
@@ -3310,10 +3317,12 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
       isModalOpen: true,
       showCardPanel: true,
       showCards: false,
+      // The params below are for FxA metrics
+      deviceId: "",
       flowId: "",
       flowBeginTime: 0
     };
-    this.didFetch = false;
+    this.fxaMetricsInitialized = false;
   }
 
   get dialog() {
@@ -3327,9 +3336,9 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
       link.rel = "localization";
     });
 
-    if (this.props.fxaEndpoint && !this.didFetch) {
+    if (this.props.fxaEndpoint && !this.fxaMetricsInitialized) {
       try {
-        this.didFetch = true;
+        this.fxaMetricsInitialized = true;
         const url = new URL(`${this.props.fxaEndpoint}/metrics-flow?entrypoint=activity-stream-firstrun&form_type=email`);
         this.addUtmParams(url);
         const response = await fetch(url, {
@@ -3338,10 +3347,12 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
 
         if (response.status === 200) {
           const {
+            deviceId,
             flowId,
             flowBeginTime
           } = await response.json();
           this.setState({
+            deviceId,
             flowId,
             flowBeginTime
           });
@@ -3508,6 +3519,7 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
       this.addUtmParams(url, true);
 
       if (action.addFlowParams) {
+        url.searchParams.append("device_id", this.state.deviceId);
         url.searchParams.append("flow_id", this.state.flowId);
         url.searchParams.append("flow_begin_time", this.state.flowBeginTime);
       }
@@ -3564,10 +3576,15 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
       target: "_blank",
       rel: "noopener noreferrer"
     }, this.getStringValue(content.learn.text))), react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("div", {
+      role: "group",
+      "aria-labelledby": "joinFormHeader",
+      "aria-describedby": "joinFormBody",
       className: "trailheadForm"
     }, react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("h3", {
+      id: "joinFormHeader",
       "data-l10n-id": content.form.title.string_id
     }, this.getStringValue(content.form.title)), react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("p", {
+      id: "joinFormBody",
       "data-l10n-id": content.form.text.string_id
     }, this.getStringValue(content.form.text)), react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("form", {
       method: "get",
@@ -3603,6 +3620,10 @@ class _Trailhead extends react__WEBPACK_IMPORTED_MODULE_4___default.a.PureCompon
       name: "utm_term",
       type: "hidden",
       value: utm_term
+    }), react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("input", {
+      name: "device_id",
+      type: "hidden",
+      value: this.state.deviceId
     }), react__WEBPACK_IMPORTED_MODULE_4___default.a.createElement("input", {
       name: "flow_id",
       type: "hidden",
@@ -7645,6 +7666,7 @@ class DSImage_DSImage extends external_React_default.a.PureComponent {
           source = this.reformatImageURL(baseSource, this.state.containerWidth, this.state.containerHeight);
           source2x = this.reformatImageURL(baseSource, this.state.containerWidth * 2, this.state.containerHeight * 2);
           img = external_React_default.a.createElement("img", {
+            crossOrigin: "anonymous",
             onError: this.onOptimizedImageError,
             src: source,
             srcSet: `${source2x} 2x`
@@ -7652,6 +7674,7 @@ class DSImage_DSImage extends external_React_default.a.PureComponent {
         }
       } else if (!this.state.nonOptimizedImageFailed) {
         img = external_React_default.a.createElement("img", {
+          crossOrigin: "anonymous",
           onError: this.onNonOptimizedImageError,
           src: this.props.source
         });
diff --git a/browser/components/newtab/data/content/assets/trailhead/card-illo-mobile.png b/browser/components/newtab/data/content/assets/trailhead/card-illo-mobile.png
index eff9628ed8fd..4a8fbcb7e403 100644
Binary files a/browser/components/newtab/data/content/assets/trailhead/card-illo-mobile.png and b/browser/components/newtab/data/content/assets/trailhead/card-illo-mobile.png differ
diff --git a/browser/components/newtab/data/trailhead.wip b/browser/components/newtab/data/trailhead.wip
deleted file mode 100644
index b4690a80064f..000000000000
--- a/browser/components/newtab/data/trailhead.wip
+++ /dev/null
@@ -1,142 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-## The following feature names must be treated as a brand, and kept in English.
-## They cannot be:
-## - Declined to adapt to grammatical case.
-## - Transliterated.
-## - Translated.
-
--facebook-container-brand-name = Facebook Container
--lockwise-brand-name = Firefox Lockwise
--monitor-brand-name = Firefox Monitor
--pocket-brand-name = Pocket
--send-brand-name = Firefox Send
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-## UI strings for the simplified onboarding modal
-
-onboarding-button-label-learn-more = Learn More
-onboarding-button-label-try-now = Try It Now
-onboarding-button-label-get-started = Get Started
-
-onboarding-welcome-header = Welcome to { -brand-short-name }
-onboarding-welcome-body = You’ve got the browser.<br/>Meet the rest of { -brand-product-name }.
-onboarding-welcome-learn-more = Learn more about the benefits.
-
-onboarding-join-form-header = Join { -brand-product-name }
-onboarding-join-form-body = Enter your email address to get started.
-onboarding-join-form-email =
-    .placeholder = Enter email
-onboarding-join-form-email-error = Valid email required
-onboarding-join-form-legal = By proceeding, you agree to the <a data-l10n-name="terms">Terms of Service</a> and <a data-l10n-name="privacy">Privacy Notice</a>.
-onboarding-join-form-continue = Continue
-
-onboarding-start-browsing-button-label = Start Browsing
-
-## These are individual benefit messages shown with an image, title and
-## description.
-
-onboarding-benefit-products-title = Useful Products
-onboarding-benefit-products-text = Get things done with a family of tools that respects your privacy across your devices.
-
-onboarding-benefit-knowledge-title = Practical Knowledge
-onboarding-benefit-knowledge-text = Learn everything you need to know to stay smarter and safer online.
-
-onboarding-benefit-privacy-title = True Privacy
-# "Personal Data Promise" should be treated as a brand and refers to a concept
-# shown elsewhere to the user: "The Firefox Personal Data Promise is the way we
-# honor your data in everything we make and do. We take less data. We keep it
-# safe. And we make sure that we are transparent about how we use it."
-onboarding-benefit-privacy-text = Everything we do honors our Personal Data Promise: Take less. Keep it safe. No secrets.
-
-
-## These strings belong to the individual onboarding messages.
-
-## Each message has a title and a description of what the browser feature is.
-## Each message also has an associated button for the user to try the feature.
-## The string for the button is found above, in the UI strings section
-onboarding-private-browsing-title = Private Browsing
-onboarding-private-browsing-text = Browse by yourself. Private Browsing with Content Blocking blocks online trackers that follow you around the web.
-
-onboarding-screenshots-title = Screenshots
-onboarding-screenshots-text = Take, save and share screenshots - without leaving { -brand-short-name }. Capture a region or an entire page as you browse. Then save to the web for easy access and sharing.
-
-onboarding-addons-title = Add-ons
-onboarding-addons-text = Add even more features that make { -brand-short-name } work harder for you. Compare prices, check the weather or express your personality with a custom theme.
-
-onboarding-ghostery-title = Ghostery
-onboarding-ghostery-text = Browse faster, smarter, or safer with extensions like Ghostery, which lets you block annoying ads.
-
-# Note: "Sync" in this case is a generic verb, as in "to synchronize"
-onboarding-fxa-title = Sync
-onboarding-fxa-text = Sign up for a { -fxaccount-brand-name } and sync your bookmarks, passwords, and open tabs everywhere you use { -brand-short-name }.
-
-onboarding-tracking-protection-title = Control How You’re Tracked
-onboarding-tracking-protection-text = Don’t like when ads follow you around? { -brand-short-name } helps you control how advertisers track your activity online.
-onboarding-tracking-protection-button = { PLATFORM() ->
-  [windows] Update Options
-  *[other] Update Preferences
-}
-
-onboarding-data-sync-title = Take Your Settings with You
-# "Sync" is short for synchronize.
-onboarding-data-sync-text = Sync your bookmarks and passwords everywhere you use { -brand-product-name }.
-onboarding-data-sync-button = Turn on { -sync-brand-short-name }
-
-onboarding-firefox-monitor-title = Stay Alert to Data Breaches
-onboarding-firefox-monitor-text = { -monitor-brand-name } monitors if your email has appeared in a data breach and alerts you if it appears in a new breach.
-onboarding-firefox-monitor-button = Sign up for Alerts
-
-onboarding-private-browsing-title = Browse Privately
-onboarding-private-browsing-text = Private Browsing clears your search and browsing history to keep it secret from anyone who uses your computer.
-onboarding-private-browsing-button = Open a Private Window
-
-onboarding-firefox-send-title = Keep Your Shared Files Private
-onboarding-firefox-send-text = { -send-brand-name } protects the files you share with end-to-end encryption and a link that automatically expires.
-onboarding-firefox-send-button = Try { -send-brand-name }
-
-onboarding-mobile-phone-title = Get { -brand-product-name } on Your Phone
-onboarding-mobile-phone-text = Download { -brand-product-name } for iOS or Android and sync your data across devices.
-# "Mobile" is short for mobile/cellular phone, "Browser" is short for web
-# browser.
-onboarding-mobile-phone-button = Download Mobile Browser
-
-onboarding-privacy-right-title = Privacy is Your Right
-onboarding-privacy-right-text = { -brand-short-name } treats your data with respect by taking less, protecting it, and being clear about how we use it.
-onboarding-privacy-right-button = Learn More
-
-onboarding-send-tabs-title = Instantly Send Yourself Tabs
-# "Send Tabs" refers to "Send Tab to Device" feature that appears when opening a
-# tab's context menu.
-onboarding-send-tabs-text = Send Tabs instantly shares pages between your devices without having to copy, paste, or leave the browser.
-onboarding-send-tabs-button = Start Using Send Tabs
-
-onboarding-pocket-anywhere-title = Read and Listen Anywhere
-# "downtime" refers to the user's free/spare time.
-onboarding-pocket-anywhere-text = { -pocket-brand-name } saves your favorite stories so you can read, listen, and watch during your downtime, even if you’re offline.
-onboarding-pocket-anywhere-button = Try { -pocket-brand-name }
-
-onboarding-lockwise-passwords-title = Take Your Passwords Everywhere
-# "many places" conveys that Lockwise is available outside of Firefox.
-onboarding-lockwise-passwords-text = { -lockwise-brand-name } saves your passwords in a secure place so you can easily log into your accounts.
-onboarding-lockwise-passwords-button = Get { -lockwise-brand-name }
-
-onboarding-facebook-container-title = Set Boundaries with Facebook
-onboarding-facebook-container-text = { -facebook-container-brand-name } keeps your Facebook identity separate from everything else, making it harder to track you across the web.
-onboarding-facebook-container-button = Add the Extension
-
-
-## Message strings belonging to the Return to AMO flow
-return-to-amo-sub-header = Great, you’ve got { -brand-short-name }
-
-# <icon></icon> will be replaced with the icon belonging to the extension
-#
-# Variables:
-#   $addon-name (String) - Name of the add-on
-return-to-amo-addon-header = Now let’s get you <icon></icon><b>{ $addon-name }.</b>
-return-to-amo-extension-button = Add the Extension
-return-to-amo-get-started-button = Get Started with { -brand-short-name }
diff --git a/browser/components/newtab/lib/OnboardingMessageProvider.jsm b/browser/components/newtab/lib/OnboardingMessageProvider.jsm
index 757f58f58557..b18493eb7837 100644
--- a/browser/components/newtab/lib/OnboardingMessageProvider.jsm
+++ b/browser/components/newtab/lib/OnboardingMessageProvider.jsm
@@ -485,6 +485,16 @@ const OnboardingMessageProvider = {
         } catch (e) {
           continue;
         }
+
+        // We know we want to show this message, so translate message strings
+        const [primary_button_string, title_string, text_string] = await L10N.formatMessages([
+          {id: msg.content.primary_button.label.string_id},
+          {id: msg.content.title.string_id},
+          {id: msg.content.text.string_id, args: msg.content.text.args},
+        ]);
+        translatedMessage.content.primary_button.label = primary_button_string.value;
+        translatedMessage.content.title = title_string.value;
+        translatedMessage.content.text = text_string.value;
       }
 
       // Translate any secondary buttons separately
diff --git a/browser/components/newtab/locales-src/cs/strings.properties b/browser/components/newtab/locales-src/cs/strings.properties
index 4247cbf47c86..76e48bf5879d 100644
--- a/browser/components/newtab/locales-src/cs/strings.properties
+++ b/browser/components/newtab/locales-src/cs/strings.properties
@@ -192,7 +192,7 @@ section_menu_action_privacy_notice=Zásady ochrany osobních údajů
 # firstrun of the browser, they give an introduction to Firefox and Sync.
 firstrun_title=Vezměte si Firefox s sebou
 firstrun_content=Mějte své záložky, historii i uložená hesla s sebou na všech svých zařízeních.
-firstrun_learn_more_link=Zjistěte více o účtech Firefoxu
+firstrun_learn_more_link=Zjistit více o účtech Firefoxu
 
 # LOCALIZATION NOTE (firstrun_form_header and firstrun_form_sub_header):
 # firstrun_form_sub_header is a continuation of firstrun_form_header, they are one sentence.
diff --git a/browser/components/newtab/prerendered/locales/cs/activity-stream-strings.js b/browser/components/newtab/prerendered/locales/cs/activity-stream-strings.js
index 206a11602508..e3ff99bd43c6 100644
--- a/browser/components/newtab/prerendered/locales/cs/activity-stream-strings.js
+++ b/browser/components/newtab/prerendered/locales/cs/activity-stream-strings.js
@@ -95,7 +95,7 @@ window.gActivityStreamStrings = {
   "section_menu_action_privacy_notice": "Zásady ochrany osobních údajů",
   "firstrun_title": "Vezměte si Firefox s sebou",
   "firstrun_content": "Mějte své záložky, historii i uložená hesla s sebou na všech svých zařízeních.",
-  "firstrun_learn_more_link": "Zjistěte více o účtech Firefoxu",
+  "firstrun_learn_more_link": "Zjistit více o účtech Firefoxu",
   "firstrun_form_header": "Zadejte svoji e-mailovou adresu",
   "firstrun_form_sub_header": "a používejte službu Firefox Sync.",
   "firstrun_email_input_placeholder": "E-mail",
diff --git a/browser/components/newtab/test/unit/asrouter/templates/Trailhead.test.jsx b/browser/components/newtab/test/unit/asrouter/templates/Trailhead.test.jsx
index e89e144c58a2..2bfbb872a7ed 100644
--- a/browser/components/newtab/test/unit/asrouter/templates/Trailhead.test.jsx
+++ b/browser/components/newtab/test/unit/asrouter/templates/Trailhead.test.jsx
@@ -93,13 +93,14 @@ describe("<Trailhead>", () => {
       data: {args: "https://example.com/path?foo=bar"},
     };
     wrapper.setState({
+      deviceId: "abc",
       flowId: "123",
       flowBeginTime: 456,
     });
     wrapper.instance().onCardAction(action);
     assert.calledOnce(onAction);
     const url = onAction.firstCall.args[0].data.args;
-    assert.equal(url, "https://example.com/path?foo=bar&utm_source=activity-stream&utm_campaign=firstrun&utm_medium=referral&utm_term=trailhead-join-card&flow_id=123&flow_begin_time=456");
+    assert.equal(url, "https://example.com/path?foo=bar&utm_source=activity-stream&utm_campaign=firstrun&utm_medium=referral&utm_term=trailhead-join-card&device_id=abc&flow_id=123&flow_begin_time=456");
   });
 
   it("should keep focus in dialog when blurring start button", () => {
diff --git a/browser/components/newtab/test/unit/unit-entry.js b/browser/components/newtab/test/unit/unit-entry.js
index 884f4c2a262d..9179fa52c1b0 100644
--- a/browser/components/newtab/test/unit/unit-entry.js
+++ b/browser/components/newtab/test/unit/unit-entry.js
@@ -286,7 +286,7 @@ const TEST_GLOBAL = {
   },
   Sampling: {
     ratioSample(seed, ratios) {
-      return 0;
+      return Promise.resolve(0);
     },
   },
 };