This is the Atari Lynx model 2 keys flex ribbon PCB scan. It's colour coded to show which keys are connected to which tracks. The original image is sourced from DevLynx, a website by Vince. The French version is translated to English with help from Google Translate.
Red : LED (it is missing on the scan)
Green : Left (or right in flip mode)
Yellow : Up (or down in flip mode)
Cyan : Down (or up in flip mode)
Blue : Right (or left in flip mode)
Rose : On (linked to Off)
Dark green : Off (connected to Common)
Brown : Back Light
Purple : Option 1 (or option 2 in flip mode)
Khaki : Pause
Emerald : Option 2 (or option 1 in flip mode)
Gray : A
Orange : B
Black : Common/Ground