What
The marketplace manager lists plugin marketplaces, which are sources Claude Code can install plugins from. Its footer shows hints for the keys you can press. For built-in marketplace rows, those hints now depend on the row's builtIn state:
"blocked": the select, update and remove hints are all hidden."off": the update hint is hidden.
Why
The footer no longer offers actions that would do nothing on that row, so you are not left pressing keys with no effect.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say what makes a built-in marketplace blocked or off.