After a few weeks of confirming its fondness of cat food, I trapped it in a cage with cat amenities, tried to pet it and got bitten.
Transcript
Scared and alert fluffy black cat on a perch in the upper corner of a big cage, at eye level with me and camera
Leave out food every day. Don't look it in the eyes directly. Move slowly and quietly. Give it space. Eventually it'll associate you with free food and MIGHT become friendlier.