Examine source code of Layout Measure

{
  "manifest_version": 3,
  "name": "Layout Measure",
  "version": "1.0.1",
  "description": "Measure elements with CAD-style dimensions and box model highlighting.",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "96": "icons/icon96.png"
    },
    "default_title": "Toggle Layout Measure"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "service_worker": "background.js"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/main.js",
        "content/inspector.js",
        "content/measurements.js",
        "content/renderer.js",
        "content/events.js"
      ],
      "css": [
        "content/styles.css"
      ],
      "all_frames": true,
      "run_at": "document_idle"
    }
  ],
  "commands": {
    "toggle-bmeasure": {
      "suggested_key": {
        "default": "Alt+M"
      },
      "description": "Toggle Layout Measure"
    },
    "toggle-dimension-end-style": {
      "suggested_key": {
        "default": "Alt+A"
      },
      "description": "Cycle dimension end styles"
    },
    "toggle-halo": {
      "suggested_key": {
        "default": "Alt+Shift+O"
      },
      "description": "Toggle contrast outlines"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{54c90782-5938-49ce-b21d-d37ccce74af1}",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "web_accessible_resources": [
    {
      "resources": [
        "content/IosevkaCustom-Regular.ttf",
        "content/IosevkaCustom-SemiBold.ttf"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}