By convention, magic words are usually written in all upper case[1] but some are suggested in lower case:
This could be how they are keyed when defined:
/** English (English) */ $magicWords['en'] = [ 'archivedtalk' => [ 0, '__ARCHIVEDTALK__' ], 'notalk' => [ 0, '__NOTALK__' ], ];
We should always use suggest upper case.
