For Cannons, it’s the shot color.
Example:color=0xc57f4c,
Colors defined by 0x followed by six digit Hex code.
Data type: uint
Can also be the color on a SHIELDS and LASERS
Shield and Laser colors need an extra two digits for alpha.
Example:color=0xc1c292f,
‘c1’ is the alpha code. ‘c292f’ is the Hex color.
For more info, see Colors