Reduce the download size by externalizing the data for the IdP drop-down list into a JSON file
Currently the WAYF loads the IDProvider.metadata.php and generates the HTML for the IdP dropdown list. The contents of the IDProvider.metadata.php file is pretty static and changes less often than the metadata file gets updated. So this information could easily be cached in the browsers to reduce the download size for users regularly visiting the WAYF.
Unlike the feed from /Shibboleth.sso/DiscoFeed the IdP JSON file should also include the category type.