Just want to document this feature in case it's useful to someone!
Pictured below is a lower corner of the rear window frame of a Mercedes 190 (W201). It has these neat transitions where most of the joint is lapped, but then it transitions to a butt joint just for the window flange portion. The joints are brazed (brass coloured metal in the joint). There are actually two similar joints in each lower corner. Lap jointed portion in orange outline and butt joint in red. The second pic shows the reverse.
Pictured below is a lower corner of the rear window frame of a Mercedes 190 (W201). It has these neat transitions where most of the joint is lapped, but then it transitions to a butt joint just for the window flange portion. The joints are brazed (brass coloured metal in the joint). There are actually two similar joints in each lower corner. Lap jointed portion in orange outline and butt joint in red. The second pic shows the reverse.