Keep git if you already use it
Git can store the prompt file. It will show a textual delta. It will not, by itself, say that the citation rule disappeared.
What you paste here
Copy the old blob into A and the new blob into B when you want that reading. AgentPrompt does not connect to your repository and does not commit, branch, or revert.
Rollback stays in git
If you want the old file back, use your own version control. This product will not push a revert.