Examine source code of vPlayBackSpeed

{
  "manifest_version": 2,
  "name": "vPlayBackSpeed",
  "version": "1.2resigned1",
  "description": "Adds play back speed controls to Vimeo videos.",
  "icons": {
    "48": "icons/fastforward.svg"
  },
  "applications": {
    "gecko": {
      "id": "vPlayBackSpeed@redronin.de",
      "strict_min_version": "45.0"
    }
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/fastforward.svg",
    "default_title": "Play Back Speed",
    "default_popup": "popup/vPlayBackSpeed.html"
  }
}