'german salt' sounds funny to me.

Let's say you're buying the most popular and common brand, Bad Reichenhall. This is your selection:

https://www.bad-reichenhaller.de/en/products.html

In most supermarkets you get almost all of these options. Disclaimer is I have never seen the one with Selenium added.

I wonder what's the mineral composition of the 'pure salt' (it certainly contains some trace minerals) and/or the famed pink salt

Wouldn't be surprising if it naturally had some fluoride