for the “or later” clause I’m assuming that there is clarification in the license to state that the license must be validated by the GNU organization or states that it must be a later/newer “GNU” based license
this is my assumption, I would have to reread (once I’m back home) the license to confirm for sure
The main difference between GPL-2.0 and 3.0 (if I remember correctly) is closure/addressing the Tivoization loophole that exists in GPL-2.0
Licensing is still confusing, even after more than a decade.
totally fair, unless you’re a lawyer or someone with OCD like me, no person would want to spend time reading all of the licensing terms/clauses