Examine source code of CATS Extension

{
  "manifest_version": 3,
  "name": "CATS Extension",
  "description": "Easily add candidates and contacts from popular websites directly into the CATS applicant tracking system.",
  "version": "3.4.22",
  "icons": {
    "16": "files/cats-16.png",
    "48": "files/cats-48.png",
    "128": "files/cats-128.png"
  },
  "default_locale": "en",
  "author": "Top Echelon",
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "action": {
    "default_icon": {
      "32": "files/cats-disabled.png"
    },
    "default_title": "CATS"
  },
  "host_permissions": [
    "https://app.catsone.com/*",
    "https://app.catsone.nl/*"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "sidebar.html",
        "assets/*",
        "files/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "catsfirefox@catsone.com"
    }
  },
  "permissions": [
    "scripting",
    "activeTab",
    "tabs",
    "identity",
    "storage",
    "contextMenus",
    "webNavigation"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.angel.co/*",
        "*://*.careerbuilder.com/*",
        "*://*.dice.ca/*",
        "*://*.dice.com/*",
        "*://*.github.com/*",
        "*://*.indeed.com/*",
        "*://*.linkedin.com/*",
        "*://*.monster.ca/*",
        "*://*.monster.com/*",
        "*://*.monsterboard.nl/*",
        "*://*.twitter.com/*",
        "*://*.xing.com/*",
        "*://*.ziprecruiter.com/*",
        "*://*.zoominfo.com/*"
      ],
      "js": [
        "content-scripts/content-script.js"
      ]
    }
  ]
}