I'm going to avoid answering the question and instead recommend finding something to do to contribute instead of doing personal work on the company's time. If you don't have anything to work on, find some. In tech, there's always something to work on. If you've gone to literally every manager and HR person in your building and exhausted the options, fine, but I doubt that to be the case. This way you learn something, it reflects positively on you, and you're not crossing into any ethical gray area.
I'm going to avoid answering the question and instead recommend finding something to do to contribute instead of doing personal work on the company's time. If you don't have anything to work on, find some. In tech, there's always something to work on. If you've gone to literally every manager and HR person in your building and exhausted the options, fine, but I doubt that to be the case. This way you learn something, it reflects positively on you, and you're not crossing into any ethical gray area.