Name this part please?

[Dhos1]

Working on installing my last door lock cylinder and ran across these…. See picture at bottom, I would assume I accidentally left them out during the install, can someone confirm please.

 

[greeneyegi]

keeps the tumbler part attached to door from inside?
just a guess

 

[Dhos1]

I’m not sure if it even goes inside the door, I don’t remember taking it out. But you know how that goes