I think it's a way more simple thing
The classic point of an online search engine is to send you to the site with the information
Now they want you to not go to the site and instead see the information they stole from it without ever leaving their site
It used to be a bridge, now it's a doorman motivated to keep you at the door
Since probably Claude 4.5 came out, pretty well as long as the code is already in a fairly good state, in a popular language, and well tested.
If you point it at some ancient spaghetti, results vary significantly, particularly with dumb "tell me what this does" style prompts