Brake adjusting star nut.
This is the brake adjuster star nut for adjusting front and rear brake shoes. These often seize up so use a bit of copper lubicant on the adjusting screw.
T1 / Beetle 1958-1979
Karmann Ghia 1958-1974
T2 / Splitscreen 1955-1967
T2 / Baywindow 1967-1979
Type 3 1962-1973