> Post-fix release: specifically, I want 4.3's Installer to be able to
> load packages with descriptions like 'Control (1.2)'. At the moment it
> tries to load a package 'Control ', which of course fails.

By "packages" I hope you don't mean simple Monticello .mcz packages.
IMO mcz filenames should follow restrictive formatting rules defined
by MCVersionName so that MC can be the best at low-level SCM as it can
be while keeping the code maintainable.

> I certainly could just commit to squeak43. I'm asking how exactly I
> should do that. Installer-Core-fbs.361 is quite a few versions ahead
> of 4.3, so should I rather copy each of the interim mczs?

If there have been a lot of changes perhaps Backporting that one fix
is appropriate?  I don't have any experience with it, but there is a
Backport button on MC.

If you don't backport, then I'm on the fence about whether to
duplicate the files in the squeak43 repository.  The main advantage
would be for diffing in that repository, but as 4.3 gets older that
will be a rare activity..