I don't know the answer to that, but thinking about it generally: If the suffix was just a single hex digit, it would work to detect a persistent tag. After, say 5 key rotations, if the last digit is still "E", then it's highly likely that the tag that's constantly in range is the same physical thing.
Meanwhile, if you're trying to use these things to track visitors to your store, you're only getting 16 bins of people. My "E" tag will be the same as 50 other people who've visited last week with the same "E" suffix.
I'm having a hard time finding the actual whitepaper on this. Hopefully someone links it in this thread.
Unfortunately, the spec is currently only available to partners in the MFi program. That is probably where parameters like the one you are asking about are defined: https://developer.apple.com/find-my/. I’m sure there will be a paper published that reverse engineers the spec once these devices are out in the wild.
Finally, the static part of the broadcast doesn’t need to be permanently static. It simply needs to rotate at a period that’s longer than the rest of the public key.
Meanwhile, if you're trying to use these things to track visitors to your store, you're only getting 16 bins of people. My "E" tag will be the same as 50 other people who've visited last week with the same "E" suffix.
I'm having a hard time finding the actual whitepaper on this. Hopefully someone links it in this thread.