What's Gutenberg, epub files, and old books written in 1900's?

https://lemmy.world/post/43762665

What's Gutenberg, epub files, and old books written in 1900's? - Lemmy.World

My location is Asia, rural, and I discovered these things. I have no real friends doing it right now? Is this just new?

I know there is a question mark at the end, but this is not an intelligible question.
I understand it perfectly, so maybe you’re just upholding your username.
Yeah maybe lol!