Speedometer tube, connects on the drive
Yup. speedo pitot fitting (for the in-dash speedometer). But, it is broken off where it plugs into lower unit, meaning the other half is probably still in there. Probable cause was removing drive unit, not realizing it was inplace there (or it was caught up on something else during removal) and snapping it off.
Will be a PITA to get the stub out, but since drive is off already, you are 1/2 way there. Easy fix to put new fitting on hose.