Firefox 6 beta
And here it is, at last. Just like the last time, the new version migrates from Aurora to Beta on Tuesday but it isn’t offered via the update channels until the next Friday, while the newer ex-Nightly is published in Aurora in the meantime.
I still think this is unnecessarily awkward for users who are interested in one specific Firefox version, or who want to avoid disabling incompatible add-ons as much as possible.