Man pages matching name crypt::u2f::server::simple in section 3pm:

Crypt::U2F::Server::Simple.3pm.en	debian 10 / libcrypt-u2f-server-perl
Crypt::U2F::Server::Simple.3pm.en	debian 11 / libcrypt-u2f-server-perl
Crypt::U2F::Server::Simple.3pm.en	debian 12 / libcrypt-u2f-server-perl