I've been looking for something like this for literal years! I was really happy to find it, and see that it actually does alphabetize playlists in the select playlist modal, however, the option to exclude the default watch later playlist from the alphabetization to keep it at the top doesn't seem to work. I've refreshed youtube several times, and updated firefox, but it still gets sorted along with everything else.
Something that I hoped gets resolved at some point, but a great add-on regardless

Awesome. Would be cool, if you could add a optional feature to set the Liked videos first, so it isn't treated as a playlist and also sorted. I hate that youtube treats it as a playlist.
Edit: Can't believe you did it. Thank you!

Finally, someone did what YouTube should have done a long time ago. I know the name of the playlist I'm looking for, and there it is! In alphabetical order! Found it on the first scroll. No more scrolling up and down looking for a playlist in some random location.

Works flawlessly! Thank you for providing a great tool that YouTube doesn't offer.

Wow, can't belive someone finally did this for Firefox!

Seriously, I've been waiting for this for years, it's extremely helpful for people that organizes the playlist.

It's also open source! Thank you so much man.

Thank you, Jordan, for creating this marvelous alphabetizing tool for YouTube playlists. I use my YT playlist in Firefox very extensively and it had become rather unwieldy. Can't believe YT didn't have a simple alphabetizing feature. This extension solved that problem for me instantly.

Sometimes the simplest extensions are the best.

This extension rearranges your playlist into alphabetical order rather than when you last updated them. For someone like me who loves to save YouTube videos for later viewing and has created many playlists over the years, it is a real hassle trying to find the right playlist.

Thank you Jordan Heale for doing what the current owners of YouTube should have done years ago!