Examine source code of Github Durations

{
  "manifest_version": 3,
  "name": "Github Durations",
  "version": "1.0",
  "description": "A browser extension that shows duration between events in the timeline on GitHub.",
  "permissions": [
    "tabs",
    "activeTab",
    "scripting"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_icon": {
      "16": "images/icon-16.png",
      "48": "images/icon-48.png",
      "128": "images/icon-128.png"
    }
  },
  "icons": {
    "16": "images/icon.png",
    "48": "images/icon.png",
    "128": "images/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "hammad.fauz_githubDurations@gmail.com",
      "strict_min_version": "91.0"
    }
  }
}