https://github.com/bitcoin/bitcoin/pull/13243/files
ec3073a27 index: Move index DBs into index/ directory. 89eddcd36 index: Remove TxIndexDB from public interface of TxIndex. 2318affd2 MOVEONLY: Move BaseIndex to its own file. f376a4924 index: Generalize logged statements in BaseIndex. 61a1226d8 index: Extract logic from TxIndex into reusable base class. e5af5fc6f db: Make reusable base class for index databases. 9b0ec1a7f db: Remove obsolete methods from CBlockTreeDB. also: PR14085 ed12d5df1 index: Fix for indexers skipping genesis block.