Examine source code of Fixing Canvas

{
  "manifest_version": 2,
  "name": "Fixing Canvas",
  "version": "1.0",
  "description": "Allows filtering just assignments in Canvas/Instructure calendar mode. More features may come in the future",
  "icons": {
    "48": "icons/CanvasIcon@0.5x.png",
    "96": "icons/CanvasIcon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.instructure.com/calendar*"
      ],
      "js": [
        "addFiltering.js"
      ]
    }
  ]
}