Varun Vasudev - Thank you for bring this to my attention!
This effort was certainly not intended to duplicate any other work - in fact, I went to some length to make sure that I didn't do so with
I was unaware of the inner QuotingInputFilter class within HttpServer2 or the fact that it also adds X-Frame-Options.
The fact that it is baked into the HttpServer2 class rather than commonly available for anyone to use and that it doesn't separate the responsibility for XFS make that filter less reusable by the overall ecosystem.
My inclination is to refactor the functionality in QuotingIinputFilter out into a generic XSS filter that can be reused by others and to integrate with it and the common XFS filter rather than relying on HttpServer2 specific filters.