Currently, Weld exposes an API that allows WFLY subsystems to register a portable extension.

However, there is no means to achieve the same for build compatible extensions.
It should be fairly simple to add a similar API so long as we can gather all of these extensions before initializing LiteExtensionTranslator here.

FTR, this came up recently in my conversation with ehugonne1@redhat.com where he tried to reuse an existing build compat. extension from SR in WFLY.

I'll keep this issue on my radar and try to send a PR soon.