The XRP Ledger is designed to be censorship resistant. Any attempt to
censor transactions would require coordinated action by a majority of
the system's validators.
Importantly, the design of the system is such that such an attempt is
detectable and can be easily proven since every validators must sign
the validations it publishes.
This commit adds an automated censorship detector. While the server is
in sync, the detector tracks all transactions that, in the view of the
server, should have been included and issues warnings of increasing
severity for any transactions which, have not after several rounds.
