Yes, but now consider that you have to forward the query. If you unpacked the ANY to individual known types at the frontend, will you only forward A, CNAME and

Yes, but now consider that you have to forward the query. If you unpacked the ANY to individual known types at the frontend, will you only forward A, CNAME and MX (which you yourself know about in your example), and omit AAAA, SRV and INFO? (And also be responsible for packing them back into a single reply, I guess?) More correctly you should probably forward the ANY as ANY, so you have to do it slightly later than "up front". And then cache the individual answer records as if they came from individual queries. I haven't fully thought this through, though, because: a) As you can see, it's not necessarily "simple"; b) it's not impossible to suss out something that makes sense, but the article at least claims that the resolver side is undefined so far, and several implementations do several different things by now. Giving up on ANY is probably for the best, at this point.