Artificial Intelligence proposes this.
The purple square including a vertical line and a star symbol (which manifests as a purple vertical line and a star on the display) signifies a sensor or electronic control unit alert in your Mercedes W205.
This is a generic alert, frequently associated with a malfunction in a particular system, and it is generally accompanied by an additional message on the dashboard that delineates the precise issue.
Proposed Measures
Verify for an associated message: The primary dashboard interface will probably exhibit language (e.g., "Inoperative", "Refer to Owner's Manual") elucidating the particular system experiencing a malfunction (e.g., Active Brake Assist, ESP, or a designated sensor).
Reinitiate the vehicle. Occasionally, the problem may stem from a transient electronic malfunction that can be rectified by powering down the vehicle, removing the key for around 30 seconds, and thereafter restarting the engine.
Exercise vigilance while driving: This indicator, when yellow or purple, indicates caution rather than an immediate red-level safety danger, allowing you to proceed to a safe place or an authorised repair facility.
Seek the assistance of a technician: Due to the symbol's ambiguity, a diagnostic scan tool (OBD-II scanner) is required to ascertain the exact error code and root cause.