addCameraLock is a macroscript that will add a new rollout (by means of a Custom Attribute) to your selected camera, which allows to quickly lock/unlock all transformations of that camera, so you don't accidentally move a carefully tracked/matched/animated camera.
Since it is implemented as a custom attribute, it travels with the .max file, so you can safely send the file to others (or to render farms) without having to worry about missing plugin files etc...