It goes round the bottom and up the rear of the bottom pulley.
From there, it goes up and to the front of the top pulley to go round the cassette of course.
Meanwhile as it crosses from the rear of the bottom pulley to the front of the top pulley, it passes the centre tab.
In order to do this, the tab is forward of the chain. If the chain went forward of the tab, it wouldn't have straight run between the pulleys.
Is that ok?
