Examine source code of Planar Overlay

{
  "manifest_version": 2,
  "name": "Planar Overlay",
  "author": "Michael Celani",
  "version": "1.3",
  "description": "Provides tooltips for MTGCardFetcher links.",
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/*"
      ],
      "js": [
        "planar.js"
      ],
      "css": [
        "css/planar.css"
      ]
    }
  ],
  "icons": {
    "48": "icons/icons8-crystal-ball-48.png",
    "96": "icons/icons8-crystal-ball-96.png"
  },
  "options_ui": {
    "page": "options.html"
  }
}