The client makes an initial request to the server:
The server responds, telling the client via
Accept-CH
that it accepts
Sec-CH-Prefers-Reduced-Transparency
. In this example
Critical-CH
is also used, indicating that
Sec-CH-Prefers-Reduced-Transparency
is considered a
critical client hint
.
Note:
We've also specified
Sec-CH-Prefers-Reduced-Transparency
in the
Vary
header, to indicate to the browser that the served content will differ based on this header value ? even if the URL stays the same ? so the browser shouldn't just use an existing cached response and instead should cache this response separately. Each header listed in the
Critical-CH
header should also be present in the
Accept-CH
and
Vary
headers.
The client automatically retries the request (due to
Critical-CH
being specified above), telling the server via
Sec-CH-Prefers-Reduced-Transparency
that it has a user preference for reduced transparency:
The client will include the header in subsequent requests in the current session unless the
Accept-CH
changes in responses to indicate that it is no longer supported by the server.