`wrench` is a tool for debugging webrender outside of a browser engine.
## headless
`wrench` has an optional headless mode for use in continuous integration. To run in headless mode, instead of using `cargo run -- args`, use `./headless.py args`.
## `replay` and `show`
Binary recordings can be generated by webrender and replayed with `wrench replay`. Enable binary recording in `RendererOptions`.
* To examine test failures, use the [reftest analyzer](https://hg.mozilla.org/mozilla-central/raw-file/tip/layout/tools/reftest/reftest-analyzer.xhtml)
* To add a new reftest, create an example frame and a reference frame in `reftests/` and then add an entry to `reftests/reftest.list`