Messenger - Theme Selector

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Messenger - Theme Selector",
  "version": "1.6",
  "manifest_version": 2,
  "description": "A theme selector for Facebook's Messenger (messenger.com) with multiple awesome looking themes!",
  "homepage_url": "https://morningtrain.dk",
  "icons": {
    "16": "img/icon16.png",
    "48": "img/icon48.png",
    "128": "img/icon128.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": true
  },
  "page_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.messenger.com/*"
      ],
      "css": [
        "css/content.css"
      ],
      "js": [
        "js/content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "img/Aj2Yt8zGd_T.png"
  ]
}