Shimano EF 35 shifter question

[RufusChucklebutty]

Can anyone tell me what the screw hole is for on the right by the number 3, I have loads of these shifters some have it some don't.

 

[Moodyman]

To install the plastic dust cover (I think).

 

[RufusChucklebutty]

Just found out its for a gear indicator, I've never seen one and don't want one. Well at least I know.