How can I read Xcode documentations in browser instead of documentation viewer?
You can see this file file:///Applications/Xcode.app/Contents/Developer/Documentation/DocSets/com.apple.ADC_Reference_Library.DeveloperTools.5_1.docset/Contents/Resources/Documents/documentation/DeveloperTools/Conceptual/WhatsNewXcode/00-Introduction/Introduction.html#//apple_ref/doc/uid/TP40004635-SW1

Which is the index of Xcode doc.

Or open it from the doc: