  * build woff/woff2 files from font package fonts-inter
  * build optimized JavaScript when needed node modules are in Debian:
    + rollup-plugin-cleanup
    + rollup-plugin-multi-entry
  * nuild optimized CSS files when needed node modules are in Debian:
    + postcss-css-variables
    + postcss-flexbugs-fixes
    + postcss-import
    + postcss-url
  * build for legacy browsers when needed node modules are in Debian:
    mdn-polyfills
  * use upstream build script when needed node modules are in Debian:
    + cheerio
  * check testsuite when needed node modules are in Debian:
    + impunity
