Examine source code of My Web Shortcuts Plus

{
  "manifest_version": 2,
  "name": "My Web Shortcuts",
  "description": "Create keyboard shortcuts to click on elements in websites and navigate/operate faster",
  "version": "2.2.5",
  "author": "contact@browsergadgets.io",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "notifications",
    "alarms",
    "https://browsergadgets.io/*",
    "http://*/*",
    "https://*/*"
  ],
  "web_accessible_resources": [
    "content-scripts/elementSelector.css",
    "content-scripts/shortcutWorker.css",
    "css/*",
    "fonts/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "My Web Shortcuts",
    "default_icon": {
      "16": "icons/16.png",
      "32": "icons/32.png",
      "48": "icons/48.png",
      "128": "icons/128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "commands": {
    "turnOnSelector": {
      "description": "Start selection in the active tab",
      "suggested_key": {
        "default": "Ctrl+Shift+Space",
        "mac": "Command+Shift+Space"
      }
    }
  },
  "externally_connectable": {
    "matches": [
      "https://browsergadgets.io/*"
    ]
  },
  "options_page": "options.html",
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "all_frames": false,
      "run_at": "document_start",
      "js": [
        "content-scripts/shortcutWorker.js"
      ],
      "css": [
        "content-scripts/shortcutWorker.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ac7a3226-fbe3-49b1-8ee8-298c2ab32320}"
    }
  }
}