Users of Gramps Web, please see the Gramps Web documentation site for details on setup, usage, where to get help, and how to contribute.
Gramps.js is the responsive Javascript frontend of Gramps Web, a modern web app that allows to browse and collaboratively edit a genealogical database, based on and interoperable with the Gramps desktop application. See Gramps Web API for the Python backend repository.
A demo deployment based on the Gramps example family tree is available here.
The documentation for using or developing Gramps.js can be found on the Gramps Web documentation site.
The developer documentation can be found at https://www.grampsweb.org/dev-frontend/.