At present, there is no official mailing list or newsgroup. Plesase use the issues section in GitLab for this.
If you have a bug or believe something is not working as expected, please submit a bug report using the issues section in GitLab.
If you have a general question or are unsure how things work, please consider posting to the issues section in GitLab.
John Ellson (for problems with builds, installation, software configuration or this web server)
Emden Gansner (for all graph layout issues)