So I found that HTML File too after a long, long search through my windows explorer and edited it.
And it worked! Thank you so much.
For anyone else hosting Seafile 6.0.7 on Windows Server.
You can change the tool-tip by changing the base.html from C:....\seafile-server-6.0.7\seahub\seahub\templates.
Just search for "Seafile", change the title and restart the server.