Man pages matching name datetime::format::iso8601 in section 3pm:

DateTime::Format::ISO8601.3pm.en	debian 10 / libdatetime-format-iso8601-perl
DateTime::Format::ISO8601.3pm.en	debian 11 / libdatetime-format-iso8601-perl
DateTime::Format::ISO8601.3pm.en	debian 12 / libdatetime-format-iso8601-perl