Manuel Pégourié-Gonnard wrote:
>> Probably a good idea. I'd prefer to have something we can all agree
>> stays, then add .set:N back later if it is wanted.  Expect an update later.
> On general principles, I think it's indeed better to add things later than
> remove things later :-)

That's the model I've used. For the moment, I've taken .set:N out, and
moved some of the support macros to l3prg. So .tl_set:N, etc. will
definitely stay from now on.
Joseph Wright