Wasn’t aware that this was cross posted here! It’s a Facit 2102. Built by Sharp.

We figured out that the left switch is constant. Konstant in swedish.

The right switch seems to add an I to the top right. Then you can do something with the rightmost row of buttons. Something which I don’t understand.

This calculator does not have a printer. It’s all screen on this computer, baby eh… Nerd!

Here’s info I’ve found online

Edit: Picture of the I with a random 6 I punched in.