Writing as: Hausgeist

Certainly a niche problem but if you are using the Cookie AutoDelete addon in your browser you may eventually find yourself waiting for an abnormal amount of “Cloudfare Security Verification” prompts, confirming that you are — supposedly — a human.

That is because your (or rather: your browser's) success in solving their proof-of-work, proof-of-space or other verification mechanisms is usually stored in a cf_clearance cookie. With addons like Cookie AutoDelete or other automated tools for clearing your cookies periodically, you will also end up clearing this cookie, so the next time you visit a given site, it will send you through the turnstile again.

For Cookie AutoDelete there is a fairly simple fix for this, although not available through the addon's settings or UI-based expression generator. You can save the following JSON snippet to a file, go to the List of Expressions in Cookie AutoDelete's settings, and load the file via the Import Expressions button.

{
  "default": [
    {
      "id": "Keep cf_clearance to avoid repeated Cloudflare verification",
      "expression": "*",
      "listType": "WHITE",
      "storeId": "default",
      "cookieNames": [
        "cf_clearance"
      ]
    }
  ]
}

This adds the cf_clearance cookie to the global allow list (based on the "*" expression) and it will no longer be deleted.

Of course you can also modify the expression to your needs and narrow the domains it applies to.