Good question. Indeed, the Welcome post says this forum is for things related to Fortran (I wrote that).
However, I wonder if we should revise it. The way I think about this is: Something (Fortran) brought us all here. Now, that we’re here, we should be able to discuss anything we want, subject to CoC.
So for now, I’d say please go ahead and start any off-topic thread. We can easily add new tags. I like the ones that @stavros suggested.