For those “hardcore” Flex-thusiasts out there, this may very well make your day!
If you routinely download the latest Flex 4 Nightly SDK builds from http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4, you’ll be pleased to know that you can now download the language reference for the very same build!
Oh no you didn’t!
OH YES, WE DID!!!1!
You can still browse the Flex 4 Language Reference at http://livedocs.adobe.com/flex/gumbo/langref/, as well as the user docs at http://livedocs.adobe.com/flex/gumbo/html/, but if you want to see the latest and greatest version of the language reference (with all the latest API changes — http://opensource.adobe.com/wiki/display/flexsdk/Rename+List, I’m looking at YOU!), head over to http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4 and download the Language Reference ZIP.