Foris is Remote Uci - it is a web GUI for configuration of system via Nuci, i.e. using Netconf.
Nowadays, Foris is in early stage of development and almost everything in it is a possible subject to change, thus there's no guaranteed API stability and all the parts should be used externally only with extreme caution, if ever...
The tools needed for developing can be installed on Debian with the command:
sudo apt install ruby-compass compass-breakpoint-plugin slimit