My comment would be that it doesn’t have to be hypothesize, it could also be reflect.
So, instead of predicting the future, they could look back at the past and analyze the strategies that helped them integrate the new information into their existing knowledge schema, or solve the problems presented.
Generally the teacher is pretty familiar with the domain of knowledge they have just presented (the context), so when a student answer applies this knowledge into a new context, it is pretty obvious.
Another phrase for “Extended Abstract” is “Unanticipated Extension”, which perhaps more clearly states the pleasant surprise of a student answer that goes beyond the given context.
E.g.: if I am teaching students how to ride a bike (as beginners), when a student “pops a wheelie” on their summative assessment it’s pretty obvious!
To create an Extended Abstract example student answer you must imagine a student who deeply understands what has been taught, and can now apply that understanding to build NEW knowledge beyond the course context.
This means not only applying it in new contexts (or “domains”), but also applying it to the past (how it used to be), or the future (how it will be).
It can also apply to within (my personal experience), or without (where we as a group may apply this new knowledge).