Author's Tracking Code Included in Source Files

Hi, I just found a Google Tag Manager script inside the index.html page of an HTML5 game I purchased with the author’s unique account number. Is this allowed?

On the same topic, is there a rule for including all assets within the source files? I noticed some games are referencing URLs to pull their assets. I suppose this is fine for something like Google fonts, but I don’t believe it is appropriate for other assets.