A Group’s Password field used for

When creating a group using the command line, I can use dscl as follows:

sudo dscl . create /Groups/testgroup
sudo dscl . create /Groups/testgroup RealName "Test Group"
sudo dscl . create /Groups/testgroup gid 999

or I can use dseditgroup:

sudo dseditgroup -o create -n /Local/Default -r "Test Group" testgroup

(here, I let dseditgroup automatically assign a GID)

Many of the posts providing guidance for creating a group also include this command:

sudo dscl . create /Groups/testgroup passwd "*"

and the man page for dscl says the parameter to passwd (in this case "*") is a user_path.
In the man page details for passwd, it only talks about it being used to change a password for a user, nothing about how it applies in the context of a group.

when I run

sudo dscl . create /Groups/testgroup passwd "*"

I am prompted for "Password:" and it accepts my admin password (only), and creates a Password field in testgroup. The value for this field displays as an asterisk.

Most (though not all) of the groups on my machine have a Password field such as this. I can scan them quickly using:

dscl . -readall /Groups Password

When I create a Password field for a group like this, does the asterisk indicate some kind of special user_path?
Does the field keep track of which user the password is for, and what the password is?
Once a Password field is created for a group, when and how might it get used?
thanks!