cschem Engine Frontend plugins 3rd party software packages project repository libraries symbol plugin-specificdata schematicssnippet data model othersoftware generatortool PCBeditor dataeditor symbol editorsymbol generator userformat Circuitsimulator schematicseditor generatortool formatconverter I/O module devicemapper slottingmechanism userscript 1 userscript 2 libraryaccess formatconverter formatconverter DRC plugin-specificdata schematicssheet data sourcee.g. text data sourcee.g. text data output convertertool locallib projectfile fileor API fileor API file e.g. fileAPI, net e.g. file fileor API file file API API e.g. file API API e.g. file fileor API