A list of every component plus which net (named wire) each pin connects to. The bridge between schematic and layout.
How it looks
Real text: exported from CORE3588 by kicad-cli
One entry of CORE3588's netlist, exported with kicad-cli sch export netlist (pin-function and pin-type lines dropped, lines joined to fit). It says: Q1 pin 1, R59 pin 2 and R60 pin 2 are one net. The full file lists all 448 nets this way.
Real geometry: CORE3588 copper, drawn from our board file (2D plan view)
The same three pins on the board, joined by copper (amber).
1Q1 pin 1
2R60 pin 2
3R59 pin 2
How it works
Where it fits
The netlist is the bridge from schematic to layout: it is the full to-do list for any router, and the reference DRC checks the copper against.
Routers get it inside the board file (Ants) or inside a DSN file (Freerouting).