Extractability
Also known as: passage extraction, quotability
How easily a self-contained, reusable passage can be lifted out of a page by a system that wants to quote part of it rather than all of it.
Extractability is about structure rather than quality. A list survives extraction intact. A table survives extraction intact. A paragraph describing five things in a row, with the fifth depending on the second, does not.
The same applies to headings: one phrased as the question a reader would actually type gives an answer engine an anchor to attach the passage to.
This is the concept most often confused with writing short. A 4000 word article can be highly extractable and a 400 word one can be impossible to quote. What matters is whether any single chunk of it stands alone once removed from everything around it.
A useful test: copy one section into a blank document. If it still makes sense with no preamble, it is extractable.