Man pages matching name datetime::format::ical in section 3pm:

DateTime::Format::ICal.3pm.en	debian 10 / libdatetime-format-ical-perl
DateTime::Format::ICal.3pm.en	debian 11 / libdatetime-format-ical-perl
DateTime::Format::ICal.3pm.en	debian 12 / libdatetime-format-ical-perl