If you're programmatically reading or writing KiCad schematics and PCBs, this is your reference sheet. It covers the S-expression format for both .kicad_sch and .kicad_pcb files in KiCad 8.x, with concrete examples of symbols, wires, footprints, traces, vias, and zones. The documentation is practical: it shows you exactly how to structure a symbol instance with properties, how net numbers work across pads and segments, and what a hierarchical sheet block looks like. This is the kind of thing you want when you're building automation for board generation or parsing existing designs, not clicking around in the GUI.
npx skills add https://github.com/o2scale/electronics-agent-kit --skill kicad-file-format