PCBmodE is an open source PCB design tool written in Python. In practice, PCBmodE is run in commandline to convert JSON files to SVG, extract changes from an edited SVG, and generate Gerbers and drill files from the SVG. Graphical editing is done in Inkscape, though much of the design is defined in the primary JSON files edited in a text editor. It doesn't currently have a notion of schematics or DRC.