in tool/colors/generate_files.dart [87:100]
void generateJson(Map<String, Color> colors, String filename) {
final StringBuffer buf = StringBuffer();
buf.writeln('{');
final List<String> lines = <String>[];
writeColors(colors, (String name, Color color) {
lines.add('\t"$name": "${color.toHex()}"');
});
buf.writeln(lines.join(',\n'));
buf.writeln('}');
File(filename).writeAsStringSync(buf.toString());
print('wrote $filename');
}