/lib/udev/keymaps/medionnb-a555 is in udev 175-0ubuntu9.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | 0x63 www # N button
0x66 prog1 # link 1 button
0x67 email # envelope button
0x69 prog2 # link 2 button
|