That is defined behavior in TCG PC Client Platform PM Profile (PTP) Specification
in Table 5 — PCR Initial and Reset Values
PCR0: 0000…..03, the ending “3” indicates locality.
In the emulator, PCRs 0-16 and 23 default to 00 when the emulator is started. But PCRs 17-22 default to ff. Why is that? Why not have them all be 00 or all be ff? (Actually, I notice PCR0 is 03 upon startup; why is that?)