Windshield seam sealer? What to use.

It appeared to me he was talking about the metal seam in the windshield channel. If he is, he needs seam sealer.

Maybe it was. Most of what’s in the picture is old dried up windshield adhesive though. And if he wants to replace the seam sealer that is there around and under the windshield adhesive, then the windshield will have to come out along with the old adhesive