What does this windscreen mark symbol mean?

[Simon50s]

I'm curious what this symbol means on the edge of my windscreen. Is it related to the fitting or to show where the wiper blade should align?

Thanks

 

[SootySport]

Never seen that before

 

[CHEZ]

I hazard a guess on sound insulating glass.
However it's just a guess

 

[Chris-P]

If it's at the top of the windscreen then i believe it refers to the 'sunscreen' section that has tinted gradient.

 

[Simon50s]

Yes, it’s at the top.

 

[Simon50s]

I just notice that there's also this one on the passenger side. It does look like the correct height where there might be an extra tint across the top of the windscreen.

 

[Bryant1998]

I’d guess it’s directions for whoever is fitting the windscreen?

 

[ben_a38p]

Means basically you can’t tint below that mark