Man pages matching name bio::seqio::handler::genericrichseqhandler in section 3pm:

Bio::SeqIO::Handler::GenericRichSeqHandler.3pm.en	debian 10 / libbio-perl-perl
Bio::SeqIO::Handler::GenericRichSeqHandler.3pm.en	debian 11 / libbio-perl-perl
Bio::SeqIO::Handler::GenericRichSeqHandler.3pm.en	debian 12 / libbio-perl-perl