Examine source code of GitHub Streaks

{
  "manifest_version": 2,
  "name": "GitHub Streaks",
  "version": "1.6resigned1",
  "description": "Add GitHub streaks back into your browser",
  "applications": {
    "gecko": {
      "id": "github-streaks@mozilla.org",
      "strict_min_version": "45.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.github.com/*"
      ],
      "js": [
        "streaks.user.js"
      ]
    }
  ]
}