General Inquiry - DLC Pack - Content.xml

Hello there, I am looking to gain some insight on a few lines in the file content.xml. Currently, I am stuck on defining these lines:

•       <overlay value="false" />
•       <disabled value="false" />
•       <persistent value="false" />

I have a "general" idea of what each of these values means, but I would like to be 100% sure by having somebody explain each one to me; or point me in the direction of a definition.

• <overlay value="false" /> This would be a file that overlaps another file of the same name or co-exists with a file of similar nature like a vehicle.meta file. 
• <disabled value="false" /> Removed, disabled not sure about this one besides the word "disabled".
• <persistent value="false" /> An object that is not deleted until a need emerges to remove it from the game's memory. 

If somebody with the appropriate knowledge could comment on this and direct me accordingly, that would be helpful. Thank you for taking the time to read my inquiry.