Man pages matching name rcsdiff in section 1:

rcsdiff.1.ja	debian 10 / manpages-ja
rcsdiff.1.en	debian 10 / rcs
rcsdiff.1.ja	debian 11 / manpages-ja
rcsdiff.1.en	debian 11 / rcs
rcsdiff.1.ja	debian 12 / manpages-ja
rcsdiff.1.en	debian 12 / rcs