If you have plugin/VT specific questions related to development, VT requests or false positive/false negative reports you can use the following category: Vulnerability Tests - Greenbone Community Forum
And finally when having question on how plugins/VTs are used (e.g. how the scanner is starting them) you can use the following category: https://community.greenbone.net/c/gse
Hope this gives a brief overview over the new communication channel here.