My Keycloak installation provides additional user details like an avatar picture that I would like to use in my Mediawiki theme. Would it be possible to add a hook between "if ( $oidc->authenticate() ) {" and the call to "findUser" in src/OpenIDConnect.php? The $oidc object should be provided as a parameter to hook handlers.
Topic on Extension talk:OpenID Connect
That is a great suggestion. Please feel free to create a feature request task for this in Phabricator (you can click the "Report a bug" link at the bottom of the sidebar on the extension page). I'll note that we're considering moving some common functionality from the plugins into the PluggableAuth extension, and this might be a candidate for that.