I recently found a header with a name of P3P , I had never seen this before, and I do not know what the real impact is on using that header.
I found some information, like this huge documentation , Some basic information and Facebook has abandoned this feature .
My question is:
What is the real use of P3P? Would it be intended to inform the user what data would be collected?
Is P3P still used? Do browsers still support this header or is it already considered obsolete?
Is there any substitute or equivalent for P3P?