There is a register game feature added.  If you register a Stardock game you get a free DLC.  Supposedly a couple more ship parts, but I haven't seen which ones.

I think you triggered the registration somehow and were given the gift code.  It is redeemable through the Steam Store.

Okay, so I finally figured out how to get the "free gift."  At the very top of the screen click on Games and then Activate a product on Steam. I have to say I was a bit disappointed as it told me I already have the DLC in my library. I guess that is because of being a founder, but still, kind of a let down.

https://forums.galciv3.com/469763/page/1/

No, Ryat's answer was what I wanted. Thanks.

Where do we actually go to register the game? I have looked but cannot find where

But I can't register because the field asking email-address doesn't accept @ - character from my (Finnish/Scandinavian) keyboard. It works other places as you can see, but not there. It is produced with key combination Ctrl+Alt+special_character. Neither other special characters work with this field, so question is:

- how/is there other methods to register?

I assume that I'm not alone with this.

Edit: never mind, I found solution allready. Thanks, Tenaka_Steo