Gulp with local HTTPS

gulpfile.js

// If you're using XAMPP on macOS, you can use "Secure-Vhost"
// @link: https://github.com/jimmyadaro/secure-vhost

var local_dev_url = "my-site.local",
    path_to_local_dev_key = "/path/to/Secure-Vhost/"+local_dev_url+"/cert.key",
    path_to_local_dev_cert = "/path/to/Secure-Vhost/"+local_dev_url+"/cert.crt";

// ...

browserSync.init({
    open: 'external',
    host: local_dev_url,
    proxy: "https://"+local_dev_url,
    port: 8888,
    https: {
        key: path_to_local_dev_key,
        cert: path_to_local_dev_cert
    },
    // Add a nonce to the browserSync script tag
    // You can add that nonce to your CSP (Content Security Policy)
    // Example: "script-src 'self' 'nonce-browser-sync'"
    snippetOptions: {
      rule: {
        match: /<\/head>/i,
        fn: function (snippet, match) {
          return snippet.replace('id=', `nonce="browser-sync" id=`) + match;
        }
      }
    }
});

// ...