Man pages matching name mhdr in section 1:

mhdr.1.en	debian 10 / mblaze
mHdr.1.en	debian 10 / montage
mhdr.1.en	debian 11 / mblaze
mHdr.1.en	debian 11 / montage
mhdr.1.en	debian 12 / mblaze
mHdr.1.en	debian 12 / montage