|NetworkManager D-Bus Reference Manual|
Each secret property in a setting has an associated "flags" property that describes how to handle that secret. The "flags" property is a bitfield that contains zero or more of the following values logically OR-ed together.
0x0 (none)- the system is responsible for providing and storing this secret.
0x1 (agent-owned)- a user-session secret agent is responsible for providing and storing this secret; when it is required, agents will be asked to provide it.
0x2 (not-saved)- this secret should not be saved but should be requested from the user each time it is required. This flag should be used for One-Time-Pad secrets, PIN codes from hardware tokens, or if the user simply does not want to save the secret.
0x4 (not-required)- in some situations it cannot be automatically determined that a secret is required or not. This flag hints that the secret is not required and should not be requested from the user.