I have M300 dual
On some projects software adds object to project after slicing are generated.
Please see picture with object and after supports has been generated and after slicing.
I couldn’t find what’s that.

after slicing

Kind Regards
Mariusz
Hello Mariusz,
The additional model you are referring to, is called a Waste Tower and it’s generated when you are printing in dual extrusion mode.
It’s a simple element which is printed next to the model during the dual-extrusion printing process. Every time the printer switches from printing with the model material to the support one and vice versa, the respective nozzle has to be either emptied or filled with the material. That’s why, the waste tower is gradually built with one layer before changing the material and afterwards. As a result, the two materials do not blend on the surface of the print and at the same time there are no material deficiencies.
Hope it clears things up 
Best Regards
Paweł