Examine source code of Brightness Lowerer Plus

{
  "manifest_version": 3,
  "name": "Brightness Lowerer Plus",
  "version": "2.0",
  "default_locale": "en",
  "description": "__MSG_extDesc__",
  "browser_specific_settings": {
    "gecko": {
      "id": "{3d8e1a30-31f5-4867-b60a-cbc2d113e6a2}",
      "strict_min_version": "115.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "action": {
    "default_title": "Brightness Lowerer Plus",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "background": {
    "scripts": [
      "defaults.js",
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "alarms",
    "scripting",
    "activeTab"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "content.css"
      ],
      "js": [
        "defaults.js",
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ],
  "commands": {
    "toggle-enabled": {
      "suggested_key": {
        "default": "Ctrl+Shift+L",
        "mac": "Command+Shift+L"
      },
      "description": "Toggle Brightness Lowerer on/off"
    },
    "brightness-down": {
      "suggested_key": {
        "default": "Ctrl+Shift+Down",
        "mac": "Command+Shift+Down"
      },
      "description": "Dim more (lower brightness)"
    },
    "brightness-up": {
      "suggested_key": {
        "default": "Ctrl+Shift+Up",
        "mac": "Command+Shift+Up"
      },
      "description": "Dim less (raise brightness)"
    },
    "toggle-bluelight": {
      "suggested_key": {
        "default": "Ctrl+Shift+K",
        "mac": "Command+Shift+K"
      },
      "description": "Toggle the blue light filter"
    }
  }
}