An XT60 connector bracket that sits under the frame in the rear LED bar spot. The LED bar attaches to the bottom of the bracket.
I used epoxy to attach this to my frame -- there will be some significant force exerted when you connect/disconnect the battery, and two screws (if you even have any long enough) probably won't cut it.
You'll want to print this upside down (so the edge that attaches to the frame is on the print bed). There will be some ugly support surfaces there, and this will hide them, leaving a clean top surface exposed on the bottom of the bracket.