"US Privacy" is [deprecated](https://github.com/InteractiveAdvertisingBureau/USPrivacy/blob/master/CCPA/US%20Privacy%20String.md), as of 1 Jan 2024. That signal is still "active" (or not deprecated) in the regs [section](https://github.com/InteractiveAdvertisingBureau/openrtb2.x/blob/main/2.6.md#323---object-regs-). Suggest tagging it as `DEPRECATED` on the way to removal.