The black ceramic frit across the windshield edges helps bonding, protects adhesive from UV
https://wiki-square.win/index.php/17_Superstars_We%27d_Love_to_Recruit_for_Our_windshield_chip_repair_Spartanburg_SC_Team
The black ceramic frit around the windshield edges facilitates bonding, protects adhesive from UV, and improves aesthetic finishing.