The HTTP Save-Data request header is a client hint that is sent to convey a preference for reduced data transmission.
The HTTP Save-Data request header is sent by a client to indicate that it wants to keep data transfer to a minimum. This may be the result of slow transfer speeds, where the client wants to have the best possible throughput for relevant data.
The only directives are
off being the default value. An example of saving data is sending an image with a lower resolution. It may not be ideal for all purposes but it is sufficient for the client’s immediate needs.
The HTTP Save-Data header is a client hint that can be used to ask the server to reduce used to inform the client