[2019] Clean install - what to back up?

Is this on Windows, Linux, or macOS?

Ah, in that case the information you are looking for would be housed within the Windows Registry. Our official position is that we cannot recommend modifying the Windows Registry - and that, if you do so, you should absolutely create a backup of it first.

If you would like to do so anyway, a member of the community created this tool which you may be interested in. Please bear in mind that we aren’t able to support third-party software.

As I said, that information is saved in the Windows Registry.