the top of the manual

Layer of Minimal Board Editor

abbr complete expression meaning
PTH Plated THrough Hole Plated through holes are placed on this layer.
MMC Metal Mask Component Mask of solder paste for the component side.
PLC PLace Component side Silkscreen for the component side.
STC STop Component side Solder Resist for the component side.
CMP CoMPonent Component side copper layer without PTH (TOP)
L2 Layer 2 Inner copper layer
L3 Layer 3 Inner copper layer
SOL SOLder Solder side copper layer without PTH (BOTTOM)
STS STop Solder side Solder Resist for the solder side.
PLS PLace Solder side Silkscreen for the solder side.
MMS Metal Mask Solder Mask of solder paste for the solder side.
DIM DIMension Tooling outline.
DRL DRiLl Drill hole (Non Plated Though Hole)
DOC DOCument For documentation. The objects placed on this layser are not exported into gerberdata.