NM28 is somewhat like a beta build of PM29, it follows the commits to the GitHub repo instead of the browser versions.
Well, so roytam1 must do something with the version number. The browser (NM28) explicitly refers itself as Pale Moon 28.10.
The addon mTube by RealityRipple doesn't install on NM28 even though it said Pale Moon 28.10 is supported.
Quoted from their site:
Supports Pale Moon [28.7 - 29.*] and SeaMonkey [2.0a1 - 2.*].
https://realityripple.com/Software/Mozilla-Extensions/muTube/
On NM27 he set it to switch to youtube mobile automatically by default. On NM28 he doesn't set this and I don't know how to do this without RealityRipple's mTube addon. youtube.com now is problematic for all versions of Pale Moon, including the latest 29.4.4.
I have to use alternative youtube client like Invidious, works but not very convenient.
https://github.com/mendel5/alternative-front-ends#youtube
https://github.com/iv-org/documentation/blob/master/Invidious-Instances.md
I currently use this public instance of Invidious:
https://yewtu.be/feed/popular