Metacity has been branched for stable 2.24. Hacking will continue in trunk as 2.25.x. This doesn’t mean that what’s in the 2.24 branch will necessarily be exactly what will ship; it does mean that what’s in the 2.24 branch is considered stable and changes which affect stability won’t affect it.
New features in trunk will not be backported to 2.24, but bugfixes will be.
Further 2.23 releases will be from the 2.24 branch and not trunk.
jhbuild has been updated (thanks, uws.)
If you don’t understand any of this, it doesn’t matter.