I've seen it come out cloudy and chocolate brown, and go in very close to clear, so, anywhere between those two.

But, I understand that some makers dye their fork oils, and some folks use ATF or hydraulic oil, so I'd say there could be a very wide range in starting appearance, as well as ending.

Maybe smell would be a more reliable test, but, again one needs to know what the starting point smelled like.

There's also viscosity.

There's also taste.  This reminds me of that that Cheech and Chong recorded skit involving the unidentified substance that looked like dog poop.

If you are talking about a LS650, I'd say we can rule out coolant, at least.

Leaks of most fluids lead to lowered levels in whatever reservoir is provided, so that's another clue.

And, in my experience, when a fork loses enough fluid, the front end starts diving and bottoming out, so there's that.

Sometimes the fork oil leaks out the screws embedded in the bottom of the forks - the bolts that hold the damping tubes in place.  The screws have a copper washer to provide a seal.

If this area is leaking the only place the oil will show is at the very bottom of the forks.