Man pages matching name xml::doctype::elementdecl in section 3pm:

XML::Doctype::ElementDecl.3pm.en	debian 10 / libxml-autowriter-perl
XML::Doctype::ElementDecl.3pm.en	debian 11 / libxml-autowriter-perl
XML::Doctype::ElementDecl.3pm.en	debian 12 / libxml-autowriter-perl