we should do this in all bridges actually

Even if the others aren't affected by the BC break?

They can be affected by any BC break we might want to do in 5.3+

All right.

Thank you @derrabus.

I'll simply discard the changes when merging up, right?

I already suggested that in the past when dealing with another experimental component (Messenger or Mailer, I don't remember). IMO, dependencies to an experimental component should never be added using the ^ operator, because marking a component as experimental is precisely about not following semver yet in it (which is the requirement for ^ to be safe).

We did so in 5.1 for notifier, and we lost the practice when preparing 5.2.
Now merged up to 5.3, using ~5.3.0

I've bumped the conflict rules as well: #39559

indeed, maybe it was notifier itself in 5.1 then 😄