Examine source code of Bookmark Player

{
  "manifest_version": 2,
  "name": "Bookmark Player",
  "version": "1.1resigned1",
  "description": "Adds a playlist functionnality to firefox bookmarks. To do so it iterates through the links in a chosen top-level bookmark folder and waits for the song in each link to finish before switching to the next link.",
  "icons": {
    "48": "icons/icon.png"
  },
  "applications": {
    "gecko": {
      "id": "bookmark.player@gmail.com",
      "strict_min_version": "47.0a1"
    }
  },
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_popup": "popups/bookmarks.html"
  },
  "background": {
    "scripts": [
      "background-script.js"
    ]
  },
  "permissions": [
    "bookmarks",
    "tabs",
    "alarms"
  ]
}