Missed the WWDC 2015 opening event? You can still watch it here!
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Thankfully, that's possible, and quite easily too! And, unlike the livestream of the event, Windows users can also access the footage problem-free. All you have to do is head over to Apple's Events site and start the 144 minute-long recording of the event. As you can imagine, playback is delivered in decent, high-quality. Without further ado, here's the link:
Things that are NOT allowed: