Examine source code of RankParse SEO Toolkit

{
  "manifest_version": 2,
  "name": "RankParse SEO Toolkit",
  "description": "Free on-page SEO analysis + domain intelligence powered by RankParse",
  "version": "1.0.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "https://api.rankparse.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "serp@rankparse.com",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "web_accessible_resources": [
    "icon/16.png",
    "icon/32.png",
    "icon/48.png",
    "icon/128.png"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "RankParse SEO Toolkit",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "open_in_tab": false,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_end",
      "js": [
        "content-scripts/metrics-bar.js"
      ]
    },
    {
      "matches": [
        "https://www.google.com/search*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/serp-tools.js"
      ]
    },
    {
      "matches": [
        "https://google.com/search*",
        "https://www.google.com/search*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/serp.js"
      ]
    }
  ]
}