*****★★★
Pressing the 1x button in the on-screen Improve YouTube interface or trying to speed up or slow down the speed using the arrows added by Improve YT do not actually affect the real video's speed, as the built-in YT menu still shows whatever previous speed was set. Note that I have my Improve YT settings set to make all videos default to 1.15x except for music ones. I believe those Improve YT buttons worked previously.