Drop this thing into your iOS app to get the family name of custom fonts your using... or you could use MacOS Font Book. At least this way you know the custom font made it to the app on your simulator or device.

GetFontFamilyNameInSwift

        for family in UIFont.familyNames {
            Swift.print("family is \(family)")
            let specificFamilyName = family as String
            for fontName in UIFont.fontNames(forFamilyName: specificFamilyName)
            {
                Swift.print("family name is \(fontName)")
            }
        }