This package minifies the HTML output of Flow using wyrihaximus/html-compress. If you set your templates with AFX, you might not need this package.
composer require carbon/compressionThe compression http middleware will modify all responses with active X-Compression: Enabled http header. This header is added to Neos.Neos:Page already so this will work for Neos right away. For other controllers, you will have to add the X-Compression: Enabled manually.