Man pages matching name mason::manual::upgradingfrommason1 in section 3pm:

Mason::Manual::UpgradingFromMason1.3pm.en	debian 10 / libmason-perl
Mason::Manual::UpgradingFromMason1.3pm.en	debian 11 / libmason-perl
Mason::Manual::UpgradingFromMason1.3pm.en	debian 12 / libmason-perl