Validator Header - Cache Validator Skips the Body

The If-None-Match header carries the cached validator tag.

highlighted = computed this step

The validator is a header

The If-None-Match header carries the client's cached tag.

\text{If-None-Match is present}

The quoted tag is parsed from the request bytes and shown in the table.

\text{validator tag parsed}

It asks whether the server's current tag still matches the cached copy.

\text{does my tag still match?}

The request sends a validator instead of assuming the cached body is fresh.

\text{validator sent}