[TSP] PKIStatus constants clarification

[tho <thomas.fossati@xxxxxx>]

I could not understand the PKIStatus constants semantics aside 
from granted(0) and waiting(3) - that I imagine as a polite way 
by which a busy server notifies a client when the processing of 
the TimeStampReq is impossible due to temporary overload...

Could someone give me some hints on how to interpret the following 
codes: 

- grantedWithMods(1) 
  To which modifications does this refers to ? 
  And moreover, which kind of modifications could a TSA inject 
  into a TimeStampResp ?  If not stated, it seems to me just 
  confusing.

- revocationWarning(4) 
  The text says - pasting from rfc2510 -: "this message contains
  a warning that a revocation is imminent.". 
  Well, but revocation of what ?

- revocationNotification(5)
  Again, revocation of what ? Seemingly this could refer to the 
  signing certificate, but how can I tell which certificate is 
  since there is no means to identify it ?

Thomas