It seems to me that Container Queries would be more suited to be a standalone spec. It has significant normative dependencies onto CSS-Contain, but isn't about defining containment itself.

I would suggest:

• moving Container Queries to a separate spec, either standalone (probably), or as part of one of the newer levels of css-conditional
• moving inline-size containment from level 3 to level 2
  (this makes contain-3 empty)

While we're at it, I wonder if something similar should happen to content-visibility being pulled into its own spec. The same arguments seem to apply, although maybe not as strongly. Alternatively, content-visibility is what becomes level 3, and we let level 2 be only about containment in the strict sense (it would differ from level 1 by adding style and inline-size containment).

I think that would help with stabilizing the core part of containment faster, and would reflect the de-facto division of labor better.

Co-editors (@mirisuzanne @tabatkins @vmpstr ), what do you think?