kiding

import UIKit
import MobileCoreServices.UTCoreTypes

if #available(iOS 14.1, *) {
    let input = Bundle.main.url(forResource: "IMG_0037", withExtension: "HEIC")!
    let output = FileManager().temporaryDirectory.appendingPathComponent("IMG_0037.GAIN_MAP.BMP")
    let source = CGImageSourceCreateWithURL(input as CFURL, nil)!

    // urn:com:apple:photo:2020:aux:hdrgainmap
    let dataInfo = CGImageSourceCopyAuxiliaryDataInfoAtIndex(source, 0, kCGImageAuxiliaryDataTypeHDRGainMap)! as Dictionary