Hi Jacqueline, good to hear from you again.
I had problems with understanding PPP also, so your not alone and I'm glad you asked.
Project-Protected-Profile (PPP). Basically it's a profile that leaders of WikiTree decide to protected against merges. Primarily, in order to be protected, a profile needs to "fit within" a project and they must be controversial or duplicated frequently. We don't want to loose any of the valuable information that is on these profiles that are 200 or more years old or notable. You can learn lots more by going to the pull-down help menu at the top of your profile and click on "Help Index." When you get there, go to letter "P" then scroll down to "Project Protected Profiles."
Click on "about" and you'll have some good information at your fingertips. All the letters in color green are links that will lead you to more insights.
In conclusion, I would advise that if you want to work on a PPPd profile, it is wise to connect with the project that protects the profile through G2G. That is what I have done above. But you will see that no one has responded so I am going to edit it and see if I can raise some answers.
Hoping this all helps.