Examine source code of Tab Closer

{
  "manifest_version": 2,
  "name": "Tab Closer",
  "description": "This extension automatically closes tabs after a certain amount of time.",
  "version": "1.8",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "https://zoom.us/postattendee",
        "https://zoom.us/j/*",
        "https://*.zoom.us/j/*",
        "https://zoom.us/s/*",
        "https://*.zoom.us/s/*"
      ],
      "js": [
        "content.js"
      ]
    },
    {
      "run_at": "document_start",
      "matches": [
        "https://*.figma.com/file/*"
      ],
      "js": [
        "content.js"
      ]
    },
    {
      "run_at": "document_start",
      "matches": [
        "https://*.slack.com/archives/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a8922cdf-bb5c-4feb-8667-8d7bf7532bec}"
    }
  }
}