This the last beta before final 1.7.1 and also last maintenance release for 1.7 branch. We are currently fully focused on Firebug 1.8 (in alpha phase) that will be ready for Firefox 5.0 (Aurora). The final 1.7.1 will follow in 1-2 weeks.
Users subscribed to AMO beta channel will be updated automatically.
Please post feedback in the newsgroup, thanks.