Examine source code of Command Center

{
  "manifest_version": 2,
  "name": "Command Center",
  "version": "1.1.0",
  "description": "Spotlight-style command palette. Cmd+Shift+Space to fuzzy-search open tabs and history; Cmd+Enter to Google search or open a URL.",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "permissions": [
    "tabs",
    "history",
    "storage",
    "https://icons.duckduckgo.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "browser_action": {
    "default_icon": "icon.svg",
    "default_title": "Open Command Center (Cmd+Shift+Space)"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "commands": {
    "toggle-palette": {
      "suggested_key": {
        "default": "Ctrl+Shift+Space",
        "mac": "Command+Shift+Space"
      },
      "description": "Open Command Center"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "command-center@local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}