Is it RC when an interpreted module upgrade breaks rdeps?

[Rebecca N. Palmer]

The formal transition process rarely seems to be used for cases that 
don't require binNMUs.  Given this, what is supposed to happen when an 
interpreted-language module changes its API, and hence potentially 
breaks its reverse dependencies?

The case I have in mind is #893360 (which makes it an urgent question as 
it's due to migrate within a day).