Examine source code of ReqBlock

{
  "manifest_version": 2,
  "name": "ReqBlock",
  "version": "3.1.1resigned1",
  "description": "A simple request blocker.",
  "icons": {
    "48": "icons/reqblock-48.png",
    "64": "icons/reqblock-64.png"
  },
  "permissions": [
    "storage",
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "background": {
    "page": "background.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{739b15ad-6b2b-465e-8a6f-aa5460cd7ff0}"
    }
  }
}