What are the 'Conventional Signs' referred to in the image?

The term 'Conventional Signs' (Условные обозначения) in the context of this map refers to the symbols, lines, and colors used to represent geographical features, political boundaries, and military fronts. These are explained in the tasks listed on the page, which instruct the user to use specific colors and markings to denote different elements of the war, such as borders, front lines, and liberated territories.