User blog comment:Syst3ms/A sketch for an — actually — formal definition of UNOCF/@comment-25337554-20180804221210/@comment-30754445-20180805040633

Also, that "walkthrough" you linked to begins with statements about cofinality which are quite wrong.

The cofinality of ω2 is most definitely not 2 (nor is it the cofinality of 2).

This kind of thing doesn't help people who are trying to understand what's going on.