Which line is safe to paste?

Read carefully, use one tool, find the thing. No attempt limit, no score — this is practice.

⚠ Everything here is synthetic. The logs, addresses and names are invented for the exercise (RFC 5737 documentation ranges, example domains). Tools are provided for educational and authorized use only. Answers are checked in your browser against values shipped with the page — you could read them in the source; the point is the practice.

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