The value
HKCU\Software\Microsoft\Windows\CurrentVersion\AdvertisingInfo → Enabled (DWORD). 1 = the per-device ID can be read by apps; 0 = denied, calls return a null/standard response. Stacked behind the Settings → Privacy & security → General toggle.
Why scope is per-account here
- The ID is per-account by design; two users on one machine independently control theirs. A tool writing it on your behalf can't claim machine-wide anonimity — it can only flip your hive.
- Microsoft honors the deny path; apps written before rules existed broke compliance on honouring. Post-2020 store policy enforces, so the flag means what it says in supported apps.
- Restore = write
1back. No reboot; next app query reads the current bit.
Preset slot
This is the first entry in ProofTune's four-key privacy preset. Its restore writes the documented default back explicitly — no guessing what you had, no mutation left behind by install.
ProofTune ProjectEngineering notes — every claim here names the bytes a real tool touches. Verify first, install second.