Man pages matching name datetime::format::flexible::lang::en in section 3pm:

DateTime::Format::Flexible::lang::en.3pm.en	debian 10 / libdatetime-format-flexible-perl
DateTime::Format::Flexible::lang::en.3pm.en	debian 11 / libdatetime-format-flexible-perl
DateTime::Format::Flexible::lang::en.3pm.en	debian 12 / libdatetime-format-flexible-perl