Sirius! A grin fills Harry’s face; he got the cloak from Dumbledore! While the letter states it more casually and politely, Sirius just about demanded to be given the invisibility cloak. According to their small discussion on what he should write to the old bastard, Sirius would have highlighted that with James dead, Sirius was the rightful heir of the Potter estate until Harry Potter comes of age, and thus, he should be in possession of all parts of the inheritance so that he can keep it properly safe. The cloak may have been loaned to Dumbledore, but the loan is over and the cloak will be returned to the rightful owner or the authorities will become involved as well as Sirius’ lawyers. Knowing Dumbledore, he’s trying his hardest to avoid any further blows to his precious reputation and raptly handed the thing over to avoid a drawn-out legal battle he would be all but certain to lose.