Man pages matching name ui::dialog::backend::whiptail in section 3pm:

UI::Dialog::Backend::Whiptail.3pm.en	debian 10 / libui-dialog-perl
UI::Dialog::Backend::Whiptail.3pm.en	debian 11 / libui-dialog-perl
UI::Dialog::Backend::Whiptail.3pm.en	debian 12 / libui-dialog-perl