This on driver side and wondering what the numbers mean? No experience with front end alignment - just curious.

Once I got bad tire switched to rear, the front end tracks straight ahead again, had been experiencing pulling to that side. Thanks...

 

That looks like a 3/4 degree cam
Looks like it is in there adjusting caster and not camber in your case
That slot is the direction of travel on some shims like yours
So, that being the left wheel, they have that cam adjusting the caster .75 degree back or more positive than a zero cam
And with the slot straight back, the camber remains at a zero set
Ford chassis master, alignment specialist
I did this for 20 years so, it is second nature to me