This doesn't look right.

[Papayoda]

While under the RV changing my oil, oil filter and coolant filter, I noticed this hole, 'missing' plug. This is between the oil pan and the transmission. You can see the end of oil pan at the very top.
My questions are:
1. Should there be a 'drain' plug where hole is?
2. What is part that has the hole?
3. Should there be fluid in it?

Transmission and engine has been working ok.
Engine and transmission info in signature line.
I have no idea how long it has been this way.
Next steps, concerns?

Thanks for your help.

[Papayoda]

I have been told that this is the flywheel housing and the hole is a weep hole. It is ok as is.