Man pages matching name gfcksum in section 1:

gfcksum.1.en	debian 10 / gfarm-client
gfcksum.1.ja	debian 10 / gfarm-client
gfcksum.1.en	debian 11 / gfarm-client
gfcksum.1.ja	debian 11 / gfarm-client
gfcksum.1.en	debian 12 / gfarm-client
gfcksum.1.ja	debian 12 / gfarm-client