An example of a common request header sent to the server is If-Modified-Since. The server returns the file only if it has been changed since a certain date and time. See HTTP.

Google's crawlers don't send the headers with all crawl attempts; it depends on the use case of the request (for example, AdsBot is more likely to set the If-Modified-Since and If-None-Match HTTP ...

HTTP headers contain data stored as name/value pairs that are passed between the server and the client. These headers are passed along with the request or the response. The Save-Data header is a ...

The IHeaderDictionary interface In ASP.NET Core, HTTP request headers are represented as an instance of the IHeaderDictionary interface to ensure consistent storage and retrieval of header values.