The spanish AMIGA version of Maniac Mansion doesn't seem to be supported, but it exists, and works by manually selecting the platform.
This is what scummvm told me to report:
User picked target 'maniac-amiga' (gameid 'maniac')...
Looking for a plugin supporting this gameid... SCUMM [all games]
Starting 'Maniac Mansion'
WARNING: Engine_SCUMM_create: Game data inconsistent with platform override!
WARNING: Engine_SCUMM_create: No unique game candidate found, using first one!
Your game version appears to be unknown. If this is NOT a fan-modified
version (in particular, not a fan-made translation), please, report the
following data to the ScummVM team along with name of the game you tried
to add and its version/language/etc.:
SCUMM gameid 'maniac', file '00.LFL', MD5 '3cf4b6ff78f735b671d8ccc2bc110b15'
Enhanced V2 game detected
Thanks, added.