The resource being extracted is the application of knowledge to tasks.

Which might sound confusing or esoteric, but then again, white collar work exists strictly because there are abstractions over the economy that give that work leverage to run machines (companies) that then proceed to optimize this extraction and value creation process in other domains.

All this to say: the creation of digital <outputs> to be used and place in locations where they mean something to someone in the context of the abstractions built up inside corporations is the thing being extracted. How many of these units of output is the thing that changes and has a relation to Jevons paradox.