> My understanding is that Martin can add, but not subtract.  Martin,
> is that correct?

Correct (see the elaboration I just sent).

> At this point, I'm not sure we know that the
> limited API is sufficient.

It's certainly not possible to easily port /all/ existing extension
modules to this ABI - but that never was the plan, only "the majority"
should be supported. It can be demonstrated that the ABI supports
"small" extension modules (xxlimited). For anything else, I'd wait
until people report limitations that they run into. Then, we can either
a strategy to rewrite the module (as also would have been possible
with all the recent additions); if rewriting is not sensible, we
have to extend the ABI (which hopefully won't be necessary often).

So I wouldn't communicate that the ABI is experimental (because
that would suggest that it may go away or change - which I do
hope will not be necessary). Instead, announcing that we are open
to extend it if there is a demonstrated need would indeed be
useful.