I wanted to get in the system all login username, is there a way to get it? tks!
No, this is not possible, and I do not believe such feature will be implemented, due to security.
If you do not want to extract users, but monitor user activity:
In the Audit logs (if enabled) you can see who used the system, what cameras they saw etc.
This is basic functionality which is not possible to expand with MIP plugins.
Note that using the ConfigApi you can read and manage roles and users.