Man pages matching name www::mechanize::formfiller::value::callback in section 3pm:

WWW::Mechanize::FormFiller::Value::Callback.3pm.en	debian 10 / libwww-mechanize-formfiller-perl
WWW::Mechanize::FormFiller::Value::Callback.3pm.en	debian 11 / libwww-mechanize-formfiller-perl
WWW::Mechanize::FormFiller::Value::Callback.3pm.en	debian 12 / libwww-mechanize-formfiller-perl