/lib/udev/rules.d/40-mga-vid-common.rules is in mga-vid-common 2.6.32-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | KERNEL=="mga_vid[0-9]*", MODE="0660", GROUP="video"
KERNEL=="mga_vid0", SYMLINK+="mga_vid"
|