Swizzle UITableViewHeaderFooterView to make header color customizable. Done in willMoveToWindow (once) because it should occur right before visible.

UITableViewHeaderFooterView+Swizzle.swift

extension UITableViewHeaderFooterView {
    private static var hasFiredOnceKey = "apollo_hasFiredOnceKey"
    
    static func apollo_swizzle() {
        // To be called in AppDelegate.didFinishLaunching
        let originalSelector = #selector(willMove(toWindow:))
        let swizzledSelector = #selector(apollo_willMove(toWindow:))
        
        guard let originalMethod = class_getInstanceMethod(self, originalSelector), let swizzledMethod = class_getInstanceMethod(self, swizzledSelector) else {
            assertionFailure("Original method or swizzled method is unavailable")
            return
        }

        let didAddMethod = class_addMethod(self, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))

        if didAddMethod {
            class_replaceMethod(self, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod);
        }
    }
    
    @objc func apollo_willMove(toWindow newWindow: UIWindow?) {
        apollo_willMove(toWindow: newWindow)
        
        let hasFiredOnce = ((objc_getAssociatedObject(self, &UITableViewHeaderFooterView.hasFiredOnceKey) as? NSNumber)?.boolValue) ?? false
        guard !hasFiredOnce else { return }
        
        objc_setAssociatedObject(self, &UITableViewHeaderFooterView.hasFiredOnceKey, NSNumber(booleanLiteral: true), .OBJC_ASSOCIATION_RETAIN)
        
        // 🚒 🚒 🚒 🚒 🚒 🚒 🧑‍🚒
        textLabel?.textColor = .red
    }
}