Oracle vs Google is a fully resolved case that cost those companies millions of dollars to litigate. This is a shakedown letter which uses those kinds of large legal damages as a threat to force a developer to stop doing something that a company does not like.
>>mindsl+(OP)
I was wondering if the precedent set by the Oracle vs Google case applied here as the user is re-implementing an API, but considering the fact that the user still has to go talk to Haeir servers, it's a different story.