This is the top layer of the cache hierarchy - it keeps as many coins in memory as can fit per the dbcache setting.
Declared in <validation.h>
[[guarded_by(0x7ff37b804b58), guarded_by(0x7ff375b4b768), guarded_by(0x7ff37df87688), guarded_by(0x7ff391af2ea8)]]
std::unique_ptr<CCoinsViewCache> m_cacheview;