After 3.5 years of ownership, I tried cleaning the fuel filler area of all the accumulated rally dust and crud.

 

What looks obviously like a drain hole didn't seem to want to be one!

 

Is there in fact a drain hole, which way does it point (yes I know it will be vaguely downwards!!), and is it rubber or something more substantial?

I have not got a Yeti, but these drain holes are to let any accumulated water escape from the area of the fuel filler pipe.  I've never looked to find where it goes, but I'll imagine that it does drop downwards and the open end will be behind the wheel arch liner.

As above........Correct.

I don't know what it's made of, but I gave mine a poke with a cable tie, and it cleared enough for me to flush it through.

When I had my Yeti, the drain hole was always blocking. I think this was as a result of a combination of a very small hole and the sticky nature of diesel. The inevitable diesel drips from refuelling combined with the dust and other small dirt particles around the filler cavity and blocked the drain hole.

I got into the habit of giving it a blast with the hose when I cleaned the car and this kept it clear.

I took the plunge today and poked about with a WD40 straw until I could detach the rubber grommet and pull it upwards a little.

All cleaned up, tested and back to normal.