Unused assets and dead code excluded from production build

Unused assets and dead code bundled into a production extension inflate the download size every user pays on install and update, slow popup initialization as JavaScript is parsed, and expose development-only test fixtures or debug data that could leak internal implementation details. ISO 25010:2011 performance-efficiency.resource-utilisation applies: every unreferenced file is pure overhead. Source maps included in packaged extensions additionally expose original source code to any user who inspects the .crx.

Configure your bundler to exclude source maps, screenshots, and test fixtures from the production copy, and verify all remaining assets are referenced in manifest.json or code.

// webpack.config.js — exclude development artifacts from production
const CopyPlugin = require('copy-webpack-plugin');

module.exports = {
  devtool: false,
  plugins: [
    new CopyPlugin({
      patterns: [{
        from: 'public',
        globOptions: {
          ignore: ['**/*.map', '**/screenshots/**', '**/test-fixtures/**'],
        },
      }],
    }),
  ],
};

After building, run find dist/ -type f | sort -k1 -t/ | xargs ls -lh and cross-reference every file against manifest.json icon declarations and HTML <script>/<link> tags. Remove anything with no reference.