The SciCat frontend is the SciCat metadata catalogue web UI, built on top of the Angular framework.
The frontend configuration is set by the config files. Files inside the config folder, with a .json extension are merged in alphabetical order, with config.v3.json applied depending on the BE_VERSION.
SciCat Live and is not supported natively by the frontend.
For an extensive list of available options see here in the SciCat frontend section.
In the default configuration config, the frontend is set to call the backend service available at backend.localhost (either v4, by default, or v3 if specified otherwise by setting BE_VERSION).
For an explanation of how setting BE_VERSION changes the environment creation see here.
Since there was a small breaking change from v3 to v4, when connecting to the backend, the BE_VERSION value controls if config.v3.json file, which is applied when BE_VERSION=v3, should be included in the configs merge process.