Examine source code of Auto Referer

{
  "name": "Auto Referer",
  "description": "Control referer to protect privacy and not break web",
  "manifest_version": 2,
  "version": "0.8.53",
  "homepage_url": "https://garywill.github.io",
  "developer": {
    "name": "Garywill",
    "url": "https://github.com/garywill/autoReferer"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*",
    "ws://*/*",
    "wss://*/*",
    "<all_urls>",
    "contextMenus",
    "tabs",
    "storage"
  ],
  "icons": {
    "128": "icon.png"
  },
  "background": {
    "page": "background.html"
  },
  "browser_action": {
    "default_icon": "icon_gray.png",
    "default_title": "Auto Referer"
  },
  "commands": {
    "_execute_browser_action": {
      "description": "Click toolbar button"
    },
    "toggle_t": {
      "description": "Toggle for one tab"
    },
    "toggle_h": {
      "description": "Toggle for one tab and new tabs opened by it"
    },
    "toggle_window": {
      "description": "Toggle for one window"
    },
    "toggle_global": {
      "description": "Toggle globally enable/disable"
    }
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f6a3df9c-c297-46a1-bb84-d9cb00b314f0}"
    }
  }
}