Whose number is this A phone number is a strong selector: expensive to acquire, hard to change, and used as an account-recovery anchor almost everywhere. It is also the selector investigators get most wrong, because the metadata everyone quotes — the carrier — is frequently stale, and because a large share of numbers now belong to software rather than to a SIM in someone's pocket. Do not call or text the subject; that is contact, not research. Step 1 — Authorized scope Read ../../ETHICS.md. Write down subject, objective, in-bounds selectors, out-of-bounds actions, and the governing jurisdicti…