Yes, I know about them and always prove extremely useful every time I receive a file with a wrong/no extension and have little clue about its content. But since the question was about how OP could work with “files with extensions” produced in Windows, I wanted to help clarify what are they, why they are used and that files do not need to be converted or whatever to be opened in Linux as it can “work with them” just fine.
Yeah, it’s easies and will make your life simpler as long as you want to do something the producer contemplated. As soon as you need a feature that is a little bit more peculiar, good luck with that.
And with this i don’t mean that Android is perfect, just that an even more closed ecosystem isn’t exactely the best choice.