Context option for PRIVACYMANAGER()

I’m currently redoing extensions.conf from 1.4 to 1.8.3.2 PRIVACYMANAGER(x,x,context) now has an option to check patterns of the callerid number entered. However I have not found any indication of how the context is to be laid out i.e. what goes into that context?

[bad-pattern]
?
?