A Mystery Climb is a written description, topo, random photo, bar napkin, interpretive dance, cave drawing, etc. that has existed through the years but for some reason, no one can figure out where the hell the climb is. They are frustrating, but are kind of fun to mull over every once in a while and perhaps check one off the list.
They usually lack some key valuable detail like a rating, name, or what formation they are on so if they were deciphered, they aren't that useful to have except for historical reasons and for fun, like how a puzzle is fun.
My take on most of these are: they were at the time worth documenting but not necessarily worth following up on as far as making sure that the world knows about them so they are unlikely to be classics.
Here are some examples for fun......
