When I signed up earlier this year, I got a free region with the normal signup process, then a free region bundle from the CTC code. I live at the edge of a region bundle, where I work is in the next one over, so I took the free region to be that one, then the region bundle where I actually live. It seems free region bundle codes are generally available (when I signed up there were also a couple of reviews that had them), and as a user I can generate a free bundle code for someone to sign up with.
A couple of weeks after signing up they sent me an offer of the whole world for £19.99.
To check what is in each, you need to do go to this page
https://www.komoot.com/product/regions , then search for a place using the search box (not zooming the map). It'll then show you on the map the region it is in, and the region bundle it is in.
Edit: do a search for "komoot free region bundle", and sites with codes will come up - e.g.
https://outbiking.co.uk/komoot-free-region/