Please add in the readme.md file a method for talking to the maintainers / developers

[Oberonc]

I dont think there is a discord server for GWT.
Freenode/##gwt is abandoned.

Surely there is a place where GWT developers can hang out and talk

[FrankHossfeld]

There is a room for chats related to GWT at matrix.org.

Install Element, login in (you might need to create an account) and search for gwtproject/gwt. You'll also find more projects related to gwt at matrix.org.

[tbroyer]

See https://www.gwtproject.org/community.html, under "other communities" (Gitter has become Matrix, but it still exists, and that's how I actually access it, from my browser)

There's no other (active) room that I know of dedicated to GWT contributors; that one Gitter room is for both GWT users and GWT contributors.