Also for the record I went through the list of requirements at https://wiki.mozilla.org/Sheriffing/Job_Visibility_Policy for tier-1 jobs and did my best to check all the boxes for these jobs. A few caveats, though: these jobs aren't quite like existing gecko test suites in that they do a combination of checking different compilation flags and correctness via reftests, but of WebRender in isolation. So things like "getting crash stacks using mozcrash" isn't applicable because we're just running rust binaries instead of firefox.
Also, these jobs are not scheduled on every push, but they do run anytime the gfx/wr folder (or if any of the taskcluster scripts that run the tests) is modified. This is effectively SETA but more precise. The jobs can be backfilled by sheriffs if needed to verify a regression.
I've added a doc page at https://developer.mozilla.org/en-US/docs/Mozilla/QA/WebRender and linked it to https://developer.mozilla.org/en-US/docs/Mozilla/QA/Automated_testing. The page provides an overview of the jobs and how to run them on try/locally (where possible).