Examine source code of Github Dates Filter

{
  "manifest_version": 2,
  "name": "Github Dates Filter",
  "version": "1.0.0",
  "description": "Add a date filter to Github issues and PRs pages.",
  "icons": {
    "48": "icons/48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.github.com/*"
      ],
      "js": [
        "extension.js"
      ]
    }
  ]
}