A GDS file is a "layout" file. It is used to produce the masks required for the photolithography process .
Open with KLayout software
KLayout is a GDS and OASIS file viewer
KLayout is also an editor that allows changing GDS and OASIS files and creating them from scratch
KLayout is free
KLayout official website: https://www.klayout.de/
KLayout Github official website: https://github.com/klayout/klayout
