The current maintainer is Eric Rostetter, assisted by the rest of the Horde developers and users.
Well, there's nothing //stopping// you from doing so. We'd much prefer that you'd link to the master copy instead; that way, you're always sure to have the most recent version.
If you do want to mirror it, give the FAQ maintainer a shout so you can get the PHP source, rather than just the resulting HTML.
The canonical location for the FAQ is http://www.horde.org/faq/.