Note that the development build is not optimized. To create a production build, run npm run build.

As an AI language model, I do not have the ability to run npm run build or any other command-line interface tools. However, I can provide you with information about the statement you mentioned.

The statement "Note that the development build is not optimized. To create a production build, run npm run build" is a common message that developers encounter when working with the Node.js package manager (npm) and building applications using frameworks such as React or Angular.

In essence, the statement is a reminder that the development build of your application is not optimized for performance and should not be used in a production environment. Instead, developers are advised to run the "npm run build" command to create a production build of their application, which is optimized for performance and can be deployed to a production server.

In summary, if you want to optimize your application for production use, you should run the "npm run build" command.