"Main stars" never have rings. The only stars with rings are the ones that are orbiting another star that is so much heavier, the star with the ring is considered a "planet", placed in a planetary orbit rather than a co-orbital arrangement with the primary star. As a "planet", the stellar forge gives it as much a chance of growing a ring as any other planet.
Planetary brown dwarfs (of all classes) with rings are quite common, but you need a pretty massive primary star for an M-class star to be considered a planet.
It is a piece of un-realism in the graphical rendering of the ED universe that has been noted before: The lighting of rings around stars is calculated the same way as that of rings around ordinary planets; the brightness of the ringed star itself is not included in the lighting calculations. So the rings are depicted as being lit only by the primary star, not by the star they are around. That means the ringed star casts an unrealistic-looking shadow on its rings and as can be seen in the OP's picture, in the case of the primary star being a black hole, the rings are un-illuminated.