Safari 7.1 Seed 1 and WebKit

Having installed Safari 7.1 Seed 1 I found it was easily rolled back by removing Safari 7.1 with a terminal command and restoring Safari 7.0.5 from the Time Machine. It all worked well.

A "but" turned up later. NetNewsWire, an RSS client, fell over on using its internal browser which also uses WebKit. It would seem possible that the 7.1 install had somehow messed up WebKit in a way that only failed on NetNewsWire.

Safari's User Agent string shows what WebKit versions are in available. After 7.1 had been removed the restored 7.0.5 showed AppleWebKit 538.43.40 and SafariWebKit 537.77.4. NetNewsWire is presumably using the later WebKit, and failing.

At this point the next option is to restore OS X. Having done that Safari's User Agent now reports AppleWebKit and SafariWebKit to be the same 537.77.4, and NetNewsWire now works again.