Man pages matching name mh-alias in section 5mh:

mh-alias.5mh.en	debian 10 / mmh
mh-alias.5mh.en	debian 10 / nmh
mh-alias.5mh.en	debian 11 / mmh
mh-alias.5mh.en	debian 11 / nmh
mh-alias.5mh.en	debian 12 / mmh
mh-alias.5mh.en	debian 12 / nmh