A big problem is that the "Jamstack" branding and the website make it deliberately unclear that "JAM" is an acronym. I can't even find it expanded on the site. Instead it contains relatively verbose explanations that never become clearer than the actual words they so desperately avoid.

It's Javascript, API, Markup. Put "pre-rendered" before "Markup" and you understand everything.

Maybe they do this because they really want to push the fact that you can serve the J and M from a CDN?