Every single Apple patch to GitHub projects is done by the same single indistinguishable user account. This isn't just "some long-running fork". It is Apple culture to actively prohibit contributions to open source projects unless 5 managers sign off on it.
They really don't like people "poaching" their employees/wildlife. Remember they illegally collided to stop other large tech firms with Apple board members from cross recruiting.
No, it’s usually just overzealous lawyers. Remember that Apple is still a pre-dot-com company and — like Microsoft — retains vestiges of those attitudes.