X_RELEASE_UNDEPRECATED_REMOVAL
Means
a name a package's src/index.ts exported at the previous release tag is gone, and that tag never marked it @deprecated
Typical cause
a removal or rename that skipped the deprecation window: its alias ships with @deprecated on main for at least one minor before a major takes it (Stability). Inert while the previous release is below v30
Fix
git show v<previous>:packages/<pkg>/src/index.ts — restore the export with a /** @deprecated */ comment naming its replacement, and remove it in the next major window