Xcode 12 12A7209 crashes for me if I just try to open the developer documentation.
Did you test on 12.2 beta (12B5018i) available on sept17 ?
Bug did not show for me on 12GM (12A7208, not 12A7209)
Bug already noticed: https://developer.apple.com/forums/thread/660490?answerId=633250022#633250022
Bug did not show for me on 12GM (12A7208, not 12A7209)
Bug already noticed: https://developer.apple.com/forums/thread/660490?answerId=633250022#633250022