Preferred HTML formatting tool?

Hello everyone,

I think it would be helpful for us to use a formatting tool for the PNG
spec. It seems like it has either already been through a formatting tool in
the past or it was very carefully manually formatted.
In either case, we should maintain that formatting in an automated way.

Do we know if the W3C already has a preferred HTML formatting tool?

If the W3C doesn't have a preference, do any of you have a favorite tool?

Thanks!