_gat is set by Google LLC via Google Analytics to throttle the rate of data collection requests.
Who sets it
Google LLC — part of the Google Analytics / gtag.js suite.
What it does
Limits the number of requests sent to Google Analytics servers within a short window. When present, it prevents GA from firing duplicate hits too quickly.
Duration
1 minute. It is one of the shortest-lived GA cookies.
Consent type
Analytics / non-essential — typically bundled under the same consent category as _ga and _gid.
Harmless on its own but part of the Google Analytics tracking suite. Block or remove via your browser's cookie controls. See how to inspect cookies.