(I'm a Mozillian.)

These are slightly sensationalist ways of phrasing the following facts:

* libxul hit linker limits on 32-bit Windows builds with profile guided optimization enabled, as it did a couple of years ago. PGO uses a lot of memory, but it's how we deliver on Windows, so it's important.

* mozilla-central and mozilla-inbound were temporarily closed to avoid further build failures whilst the issue was explored. Other trees (try, services-central, etc. etc. etc.) remained open.

* some recent large changes to libxul were backed out in order to relieve pressure on linking.

* mozilla-central is now open for landings that aren't libxul-related, apart from those to trim it down. JavaScript and other landings continue unabated.

See Bugzilla for the full scoop.