Hi Andrew, "Features that show up in the "SolderMaskLayer" are actually _apertures_ in the solder mask (places where the copper will _not_ be masked), " True. "The resulting Gerber file will be understood accordingly by the PCB manufacturers." True except possibly for the special case where there may be no apertures at all in the soldermask. Please see these threads: [https://easyeda.com/forum/topic/Gerber-Generator-not-creating-bottom-solder-mask-properly-a0b2833339464b73851aa60237c8e157](https://easyeda.com/forum/topic/Gerber-Generator-not-creating-bottom-solder-mask-properly-a0b2833339464b73851aa60237c8e157) [https://easyeda.com/forum/topic/PCB-ordered-to-be-Matt-Black-but-came-with-no-colour-32a72106847a43c99fc691dcfba75cbf](https://easyeda.com/forum/topic/PCB-ordered-to-be-Matt-Black-but-came-with-no-colour-32a72106847a43c99fc691dcfba75cbf)

Thanks! What I am seeing on JLCPCB for my order meshes with this too. In fact, the special case with no apertures happened, and they rejected my design (luckily, as I'd intended for there to be no mask instead).