On Windows, the LibreOffice installer claimed that Firefox was using files that needed to be updated. This Reddit thread has some background on why that is:
Yes, I saw this installing 7.3.0.3 this morning: I started the computer, opened Firefox, then downloaded and installed LibreOffice. I have an aversion to closing my browser (and all of its tabs) unnecessarily, so I looked this up and found the Reddit post.
https://www.reddit.com/r/libreoffice/comments/aoqmvr/libreof...
In short, you can probably ignore it and continue.