Man pages matching name webservice::validator::css::w3c in section 3pm:

WebService::Validator::CSS::W3C.3pm.en	debian 10 / libwebservice-validator-css-w3c-perl
WebService::Validator::CSS::W3C.3pm.en	debian 11 / libwebservice-validator-css-w3c-perl
WebService::Validator::CSS::W3C.3pm.en	debian 12 / libwebservice-validator-css-w3c-perl