At a roundtable at the recent Bay Area LLVM Dev meeting, there was a discussion regarding the process LLVM uses to execute releases.
A lot of the teams who heavily contribute to LLVM development do independent releases closer to trunk and aren't as engaged with the official release process. So the discussion turned to downstream consumers of llvm, like Rust. I haven't paid terribly close attention but from what I recall Rust does try to take content from upstream llvm around the time of those releases. Would it be valuable for some member(s) of the Rust dev team to engage with the llvm release-testers list and give feedback about any regressions encountered (or lack thereof)? It would be a mutual benefit to LLVM and Rust. This is something that Andrew Kelley has been doing with Zig, for example.