cic
The sky130A technology description for ciccreator and cicpy, the tools that generate transistor level layout from a .cic description.
Where the PDK tells magic and KLayout how to check a layout, this file tells ciccreator how to draw one: which GDS purpose each abstract layer maps to, how wide a metal may be, how much enclosure a via needs, and which layers the router may use in which direction.
Two names, one file: sky130.tech is a symlink to sky130A.tech, because some flows ask for the variant letter and some do not.