Man pages matching name http::headers::actionpack::mediatypelist in section 3pm:

HTTP::Headers::ActionPack::MediaTypeList.3pm.en	debian 10 / libhttp-headers-actionpack-perl
HTTP::Headers::ActionPack::MediaTypeList.3pm.en	debian 11 / libhttp-headers-actionpack-perl
HTTP::Headers::ActionPack::MediaTypeList.3pm.en	debian 12 / libhttp-headers-actionpack-perl