Describe which session properties are available in a policy condition script

Bug description

There's no information on which session properties are available when using session.getProperty() in a policy condition script.

Working for example is,
session.getProperty("AuthLevel")
session.getProperty("authInstant")

But others return null:
session.getProperty("MaxSessionTime")
session.getProperty("TimeLeft")

Attached screenshot is a possible starting point.