There is no such thing as a "PRIA Record" (although we might see that soon thanks to colgan).
PRIA is a law which requires some air carriers to keep records, and to furnish them to another employer who is considering you for a pilot job.
An air carrier must obtain your past records when considering you for employment. This will include past aviation employers and your FAA records (plus DOT and NDR). FAA violations will show up, but I do not believe that pink slips will appear although there may be other means of obtaining them (FOIA).
A non-air carrier (part 91) does not have to keep records...but if they do, they must furnish them if asked. Obviously some 91 operators do keep records.
About the five year limit...the PRIA law does not allow you to request or furnish records older than five years. The PRI law prevents past employers from getting sued for providing PRIA records...but if they furnish records older than five years which are NOT required by PRIA, I suspect they could open themselves up to a lawsuit. For that reason I think larger companies would probably not provide more than five years of data. A small company might not have legal staff to provide guidance on this, so a clerk might just photocopy your entire record and mail it (I have seen this at two companies). But if you are talking airlines, it should only go back 5 years.
FAA records will also be reported going back five years...except revocations which are reported forever.
Not sure how far back DOT and NDR records go.
As far as WHAT gets reported...basically any and all training and discipline events related to being a pilot. In the past, non-aviation disciplinary actions were not reported (ie punching your CP in the mouth), but I think that might have changed.