Browser & Web Performance · Junior · Question 40 of 75

What is an `ETag` used for?

✓Correct answer: Identifying a version of a resource so the cache can revalidate it with If-None-Match
2Encrypting the response body
3Tagging which CDN served the response

Explanation

If the resource hasn't changed, the server answers 304 Not Modified with no body, and the cached copy is reused.

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