When I looked at the source, around 2015, there wasn't much difference, other than the name. People called "Google" were allowed to name the result of building

When I looked at the source, around 2015, there wasn't much difference, other than the name. People called "Google" were allowed to name the result of building it "Chrome". If you weren't Google you had to call it Chromium, and could of course apply patches or change the build flags. The functional differences I saw then were all a result of patches that were applied by my distribution.