Currently the Contact details section of the identity.kde.org (https://identity.kde.org/index.php?r=people/editContactDetails) only contains the option to add an IRC Nickname or Jabber ID. With the increase in usage of Matrix by KDE and rooms being hosted on kde.org, it would be nice to have the option to insert a Matrix (https://matrix.org/) identity address. I believe this would take form of "@username:example.com".
KDE Identity is in the process of being phased out and retired i'm afraid so we won't be making any changes to it. It's successor will not be collecting any contact details except email addresses as we have little use for that information.