Examine source code of GitHub Resizer

{
  "manifest_version": 3,
  "name": "GitHub Resizer",
  "version": "1.0.0",
  "description": "Widen GitHub pages between the native 1280px default and the full viewport, in 1% steps.",
  "homepage_url": "https://github.com/R0GGER/firefox-github-resize",
  "browser_specific_settings": {
    "gecko": {
      "id": "github-resizer@rmeij.local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "action": {
    "default_title": "GitHub Resizer",
    "default_popup": "popup/popup.html",
    "default_icon": {
      "48": "icons/icon.svg",
      "96": "icons/icon.svg"
    },
    "theme_icons": [
      {
        "light": "icons/icon-light.svg",
        "dark": "icons/icon.svg",
        "size": 48
      },
      {
        "light": "icons/icon-light.svg",
        "dark": "icons/icon.svg",
        "size": 96
      }
    ]
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "*://github.com/*",
    "*://gist.github.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://github.com/*",
        "*://gist.github.com/*"
      ],
      "js": [
        "content/content.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ]
}