I don't know. Maybe by using Wireshark on my Liquid node to vaguely capture traffic and try to vaguely find who might be the block signers if I can capture the right traffic from a peer. That being said if we can minimally agree the information from Coin Telegraph and mempool.space is correct, at least you have proof there was 1 block signer in Japan: https://cointelegraph.com/news/liquid-network-block-production-resumes-following-transaction-processing-issues

At the end of the day for any community there is some trust involved. 1-2 years ago I got rug pulled by Fiatjaf around 80-90 sats in a telegram group. Given that there is at least a good track record for Liquid since 2018 I feel confident we may not be rug pulled. That being said to my friends I recommend them Bitcoin, not Liquid or Fedi.