Best known invalid block, tracked to detect a longer invalid chain than the valid one.
Declared in <validation.h>
[[guarded_by(0x7fd753e2df98), guarded_by(0x7fd74dcef648), guarded_by(0x7fd74a14d248), guarded_by(0x7fd75e70e4d8)]]
CBlockIndex* m_best_invalid = {nullptr};