https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html has two links labeled "libs team reviewers" that lead to https://github.com/rust-lang/highfive/blob/master/highfive/configs/rust-lang/rust.json, which doesn't exist. It also says to "either ping @rust-lang/libs-api or leave a comment asking about the status of the feature", but it's not clear what "ping" means here; it seems to be distinct from "leav[ing] a comment", and even if it does mean leaving a comment with that tag in it, that doesn't appear to work (at least it doesn't get highlighted in the rendered comment like a user would be).