How do I decipher the Detailed Edit History in Bridge?

I teach HS photography. I have the preferences set in photoshop to record detailed editing information in the metadata. I need to see that they have actually done certain things (and try to catch sharing of files--its kind of futile but I do catch it sometimes.)

But sometimes I don't know what the terms mean. 

For example, 'Open False, true'. What does that mean? 

Is there someplace I can go to define all the terms? I know there are others.