Netlify has introduced a custom `Netlify-Vary` header that allows developers to control how cached content is served and updated based on various conditions, such as query parameters, headers, cookies, languages, and countries. This feature provides more flexibility in caching dynamic assets and can help improve cache hit rates, reduce unnecessary cache updates, and simplify caching logic for complex use cases. With the new `Netlify-Vary` header, developers can specify instructions to vary on different parts of the request, such as query parameters, headers, cookies, languages, or countries, to uniquely identify cached objects in Netlify's CDN. This feature is available now and can be explored further through a demo repository and documentation.