[leni536]

What's the actual license?

[itslennysfault]

Creative Commons (it's at the bottom of the page).

Specifically:

Creative Commons Attribution 4.0 International License http://creativecommons.org/licenses/by/4.0/

[leni536]

>No additional restrictions

Does it mean that one can't trademark a logo from this site?

[weinzierl]

Copyright and trademark are independent, you could have one without the other.