Examine source code of Tabs Unloader

{
  "name": "Tabs Unloader",
  "description": "Unloads the oldest tabs when the count of loaded into memory tabs exceeds the limit set by user",
  "homepage_url": "https://github.com/derejar/tabs_unloader",
  "version": "1.0.1",
  "manifest_version": 2,
  "author": "derejar",
  "permissions": [
    "tabs",
    "sessions",
    "menus",
    "storage"
  ],
  "background": {
    "scripts": [
      "src/utilities.js",
      "src/menu_option.js",
      "src/tabs_unloader.js",
      "src/main.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Tabs Unloader",
    "default_popup": "src/popup/tabs_unloader_popup.html",
    "default_area": "navbar"
  },
  "icons": {
    "64": "icons/64x64.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tabs_unloader@derejar.com",
      "strict_min_version": "100.0"
    }
  }
}