How do I watch it?
I exported it as a bunch of mp4's. Most episodes of seasons 1, 2, and 3, are unaltered while most of the episodes in seasons 4, 5, 6, and 7 are altered — but all episodes have been upscaled using the Gaia model in Topaz Labs' Video Enhance AI.
The best way to watch this edit is on a media server where you can just drop in the edited version of the show as a replacement for some episodes in an existing collection of Buffy. If that doesn't work for you, you can playback the video on Google Drive or download the mp4's and watch them on your computer.
As with all fan edits it is asked that you only watch this project if you have access to a legally obtained copy of the show yourself — in order to mitigate legal troubles and any potential market impact to the creators.
Here is the Google Drive Link.
(Again, nothing from season 1 was edited, so I did not include it here. If you want a quick way to watch Season 1 the official Facebook page is currently streaming it for free.)