https://mariadb.com/kb/en/library/server-system-variables/#max_user_connections

The description current says:

"Maximum simultaneous connections permitted for a user account. If set to 0, the default, there is no per-user limit. The session value is read-only and takes the global value unless there's a nonzero MAX_USER_CONNECTIONS value for the user. Previously having a minimum value of 0, from MariaDB 5.3, max_user_connections can be set to -1 to stop users from connecting to the server. The global max_user_connections variable does not affect users with the SUPER privilege."

This isn't very clear. Recommendation:

"Maximum simultaneous connections permitted for each user account. If set to 0, the default, global user connection limits are disabled and the variable is read-only. The session variable is always read-only, only privileged users can modify users' limits. The session variable is equal to the global max_user_connections value unless the specific user MAX_USER_CONNECTIONS (https://mariadb.com/kb/en/library/create-user/#max_user_connections) is a nonzero value. If both global max_user_connections and specific user MAX_USER_CONNECTIONS are set, the user specific MAX_USER_CONNECTIONS value is used. From MariaDB 5.3, max_user_connections can be set to -1 to stop users from connecting to the server. The global max_user_connections variable does not affect users with the SUPER privilege."

Additionally, the value for Dynamic should be changed or a note added. It isn't dynamic when max_user_connections = 0, which is the default.