I found it (once again) whilst trying to report a bug against "nvidia-graphics-drivers-340" (currently in the Ubuntu xorg-edgers PPA only).
There is more than just the Package Chooser bug though; I had first added an also-affects "nvidia-graphics-drivers-340 (Ubuntu)" on bug #1247736 which *was* accepted, even though the package doesn't exist.
Eight years later this bug still exists :(
I found it (once again) whilst trying to report a bug against "nvidia- graphics- drivers- 340" (currently in the Ubuntu xorg-edgers PPA only).
There is more than just the Package Chooser bug though; I had first added an also-affects "nvidia- graphics- drivers- 340 (Ubuntu)" on bug #1247736 which *was* accepted, even though the package doesn't exist.