Icons are exactly that, icons representing an asset in the game's GUI. Mashinky game icons are PNG textures with alpha channel. Icons support Company colors. For that purpose an icon consists of two parts. One is the whole vehicle with white area to be painted by company color and the other is a mask of the area to be painted by company color. An example follows.
Above picture shows the icon and its dimensions and the alpha channel. One icon texture can contain icons for multiple vehicles. To differentiate between multiple icons in one file, the game uses a tcoords.xml file that determines the coordinates of every icon in the file and its color mask. T
Vanilla game icons are located in DriveLetter:\...\Steam\steamapps\common\Mashinky\media\map\gui
Coord definiton looks as follows:
<Coord id="8694AA88" x="0" y="0" w="40" h="25" />
<Coord id="8694AA89" x="0" y="25" w="40" h="25" />
First line represents the whole icon and the second is for the color mask. Icons are then referenced in game assets main config file .xml