Koreader crashed, I deleted and reinstalled, it's set up exactly as I had it. How?

Hello! I'm just curious and wanting to understand what happened.

I loaded a bunch of ePubs on my Kobo Libra 2, and after that, Koreader wouldn't open but instead just closed itself. So I deleted the Koreader file and the other file that is usually installed with it. Then I reinstalled all over again.

I was expecting to have to set everything up again, the custom font, all the settings how I like it - but when I opened Koreader, I was very pleasantly surprised to find that everything was exactly as I had left it, even the custom font I had installed before.

I am super happy about not having to set it all up again, but I'm also really curious how that happened, if I deleted all the Koreader files off the Kobo before I reinstalled again?

Thanks :)