It means whatever is convenient. If you are looking to monetize knowledge you would use it like "your car", half way your books are just books you've purchased a copy of, at the other end your car is now mine.

I found an abandoned bicycle 10 years ago. I have since replaced nearly all parts of it. I would give it back if you can prove it is yours but who owns the bicycle of theseus is more of an opinion.

I refer to it as my bicycle.