Examine source code of Control for Reddit

{
  "manifest_version": 3,
  "name": "Control for Reddit",
  "version": "1.3.5",
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "*://*.reddit.com/*",
    "*://old.reddit.com/*"
  ],
  "description": "Lets you take control of your time by limiting reddit features",
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@control.org"
    }
  },
  "icons": {
    "48": "icons/control_simple.svg"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://old.reddit.com/*"
      ],
      "js": [
        "js/oldreddit.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "*://*.reddit.com/*"
      ],
      "js": [
        "js/control.js"
      ],
      "run_at": "document_start"
    }
  ]
}