It piqued my curiousity too so I had a little look. It's called an Impressum. I think OP is incorrect that personal websites need to list a phone number and address - it seems to just apply to commercial entities.
See my reply to another commentor [0].
In short, the situation is a little confusing since even though your private blog may not be commercial, it may be regarded "businesslike" nontheless [1].
That being said, this legislation has been in place for some years now. I am not aware of any private person actually having had to face legal ramifications because of this and personally I would just omit it and say bring it.
Still, you see lots of private German blogs which do have an inprint, if you look out for it.
https://law.stackexchange.com/a/23395
https://www.ionos.co.uk/digitalguide/websites/digital-law/a-...