Do we want to add it to configurationExtensionPoint.ts yet? I think that's essentially extension API, we could leave out so it's a hidden property for builtin extensions until we're sure we like the shape.

@roblourens I agree. I've removed the change to configurationExtensionPoint.ts

What are the other tags that can be supported and how can this be leveraged as an end user?

What are the other tags that can be supported

Tags can be literally anything. We will support tag based search just like we do for extensions.

how can this be leveraged as an end user

Any kind of filtering that goes across the existing groups that you see in the toc and which cannot be easily achieved by text search are the best use cases for tags. No bright ideas at the moment as to what other examples for tags.