In meta=allmessages API, amincludelocal seemingly does nothing.

For example, I would expect this query to return data about 'timezone-cet' and 'timezone-cest' messages, but it doesn't:
https://de.wiktionary.org/wiki/Spezial:ApiSandbox#action=query&format=json&meta=allmessages&amincludelocal=1&amfilter=timezone-&amlang=de

The messages definitely exist, and data about them is returned if they are named directly:
https://de.wiktionary.org/wiki/Spezial:ApiSandbox#action=query&format=json&meta=allmessages&ammessages=timezone-cet%7Ctimezone-cest&amincludelocal=1&amlang=de