I just tried to find and download the CSW Client for ArcMap so that I could use it with ArcGIS 10.3 for Desktop to test an answer at Is there public OGC Catalog Service (CSW) available which lets ArcGIS for Desktop with CSW Client Add (WMS) To Map?
I located a Geoportal Server Downloads page on GitHub and clicked on the Desktop Clients for ArcGIS 10.2 link because there was not a link to Desktop Clients for ArcGIS 10.3.
When I tried to install it all the same I was blocked by a message saying:
CSW Client for ArcGIS Desktop requires ArcGIS 10.2 for Desktop CSW
Client for ArcGIS Desktop will not be installed at this time.
Is there a CSW Client for ArcGIS 10.3 Desktop available for download anywhere?