For Rust on Linux it's a bit more involved because they use nightly features, which can change from day to day. In practice there's an implicit tiered strata, w

For Rust on Linux it's a bit more involved because they use nightly features, which can change from day to day. In practice there's an implicit tiered strata, with features that rarely change and features that frequently change in bursts. I would like it if we formalized that distinction a bit. We already mark when a feature is very likely to change (unstable_features), but not when they are very close to being stabilized.