The location of thoughts is the same as the "location" of awareness the moment the thought is generated (neurons fire in the brain) and this is pretty much how thinking about objects in the real world works. By default there is thought about every single object and especially animals (this include us, great apes

) and it is not in head but it is out there where object is and it describes this object to us. That is why object appear there and not here. Typically however at the moment of perception we do not have any thoughts which are let's say conclusive and any additional thinking about object need to be continued and when this happens attention moves inwards. When you try to observe where you are or where thoughts are you create this perception of thinking from inside head. When you do not think about this from where you think then thoughts are location-less. Because however we always expect some perspective (this comes from our animal past filled with dangers of living) mind constantly creates this scene of observing to give itself some workable perspective. For mind any unfinished thought is potential threat and any time you check where you are is like "am I gonna be fine or do this thing is going to eat me?" hence dukkha.
Some people who spent a lot of time on practice employ sophisticated techniques of perception. When you know how brain works and even if you do not really care but spent years on observing and optimizing perception you learn how to do it more efficiently and to get nicer perception. One of the effects of such optimizations is uninterrupted processing of objects of perception until they are completed. When all objects are processed there is no need to create perspective of watcher to check how you are in relation to objects. This completing processing of objects also gives the experience of "doneness" that people report. It is in relation to objects of perception, not their practice but this is all encompassing experience so without specific investigation regarding what it is it is hard to say and since people think a lot about ther practice they mix things, especially that thought about practice also feels done... fun fact

But ending this digression, it is also worth noting that when there are no specific objects to process perception switch to a kind of wide mode where it only quickly assesses if there are new objects and when any new object appear but is fully processed before creating need to check where you are in relation to this object then there is no need to feel dukkha caused by being threatened, no need to experience watcher pespective.
It is one way this can be looked at.
Strategies people employ when processing reality have some differences but the goal is one: to avoid existence of certain activity in brain. This some people can accomplish by processing things quickly in-place by putting right effort in to perception to not have to re-do it (hello Chris :lol

, by utilizing concentration, by using sophisticated control of activation states of parts of brain which process objects to block them right after they fire to force processing of the same object by the new parts brain in the same way and aggregating results to eventually (if input from new brain part doesn't change anything in given perception) conclude processing "done" before ever letting unfinished thought to linger (guess, I should say hello myself

) or many other. My own solution seems overengineered because it was developed to improve eye sight and I cannot rely on data from eyes from one moment to see sharply from faw away. It was not meditative attainment. From what I experienced when trying other methods which other people use they bring similar results, though each gives distinctive experience and they all have their advantages and disadvantages.