Cooker is always in flux but at certain moments, snapshots are made.
Does this mean there will be no further stabilizing branch after 9.2, to eventually get a 9.2.1?
Sure, the situation is a bit different than in normal sw development, where e.g. Mozilla 1.4 got the chance to mature to 1.4.1 (soon to be released), while the main line grew into the more unstable 1.5 alpha and beta.
