What is "Profile Passcode"?

What can the “Profile Passcode” regulate in the APP Profiles settings in iOS?
The Zscaler help page does not have any information on this.

Hello Hiroaki,
This settings for the old Zscaler agent (SecureAgent). It is not supported with the current Client Connector’s versions. We still have a few accounts using SecureAgent and that is why we never removed it.