...
The Service Catalog (ServCat) is a metadata catalog. It holds capabilities information on (mainly) OGC web services in a PostgreSQL database. It can be filled and searched using a REST-based API (implemented in Java).
Currently a ServCat instance is operated as source for the search functionality in VEF-based viewers.
Please have a look at the Service Catalog page for more details.
The source code is accessible on Gitlab.
...