No idea about the source, but the report says (they are amazingly bitter, it sounds like it's written by a supporter
):
Rangnick and Mintzlaff fought weeks for Embolo, tried to sell him the city, the club and the environment best for his development, but then Jose Mourinho offered more money (they are insulting the city of Manchester
and more or less argue that he won't get any game time at all) – they reckon he could earn around €5-6m compared to the €3m proposed by Leipzig. As of today Leipzig have dropped out of the race to sign the Swiss talent.