Examine source code of Last Resort

{
  "name": "Last Resort",
  "version": "0.8resigned1",
  "description": "Override artist images on Last.fm!",
  "permissions": [
    "activeTab",
    "storage",
    "https://*.last.fm/*",
    "webNavigation"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "applications": {
    "gecko": {
      "id": "lastresort@jakeledoux.com"
    }
  },
  "browser_action": {
    "default_title": "Click to replace images on this page.",
    "default_icon": {
      "48": "icon_48.png",
      "128": "icon_128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "icons": {
    "48": "icon_48.png",
    "128": "icon_128.png"
  },
  "manifest_version": 2
}