I tweaked the operation a little, LGTM re:op addition.

Needs entry in FIRRTLVisitor (Statement?).

Verification might be reasonable to add to the operation, depending on how big these get (mostly sanity checking the attribute and that operand count matches, I think)?

While these have (and introduce a name, as a sort of declaration) they aren't expected to really act that way, I think is where things landed.
(can't target with annotations, so on)

(CI failure will be fixed by in-flight PR updating the artifact action)

I think this is good to go and a good starting point.

A verifier (in a future PR) that checks the shape of the augmented bundle type and the number of variadic arguments would be nice.

Yes! And maybe tweak the attributes to more directly contain what's needed (vs DictionaryAttr), reducing need to inspect their contents as part of the operation's verification other than minor details (and asking/counting how many leaves)...?

I'll tweak the operation to check all operands are ground types before merging 👍 .