OpenStack packstack heat domain related options

Issue

We use packstack to install node and after installation we see below heat domain related parameters set. But we don't see the values in packstack configuration file. I am trying to understand why do we need them at all and how they are set? Looks like packstack generate them randomly.

# Keystone domain ID which contains heat template-defined
#stack_user_domain=<None>
stack_user_domain=5cc195df4b874495b996e640eda01fb8
# users and projects in the stack_user_domain. (string value)
#stack_domain_admin=<None>
stack_domain_admin=heat_admin
# Keystone password for stack_domain_admin user. (string
#stack_domain_admin_password=<None>
stack_domain_admin_password=0123456789123456