Examine source code of Old Github UI

{
  "name": "Old Github UI",
  "version": "2.3",
  "manifest_version": 2,
  "description": "GitHub changed their UI on 2020-06-23, this extension brings a few items back to their classic look.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*",
        "https://gist.gihub.com/*"
      ],
      "css": [
        "headers.css"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://github.com/*/*"
      ],
      "exclude_globs": [
        "https://github.com/*/*/settings*",
        "https://github.com/*/*/community*"
      ],
      "css": [
        "repo-content.css"
      ],
      "run_at": "document_start"
    }
  ]
}