Glossary
Windows-gather.db
Windows 11 SQLite database holding the Windows Search gatherer tables SystemIndex_Gthr and SystemIndex_GthrPth: crawled documents and the folder scope tree.
Windows-gather.db sits next to Windows.db on Windows 11 and has its own -wal file. It contains the gatherer's bookkeeping: SystemIndex_Gthr (ScopeID, DocumentID, FileName, LastModified, TransactionFlags…) and SystemIndex_GthrPth (Scope, Parent, Name), a tree from which folder paths can be rebuilt.
DocumentID matches the property store's WorkId. Comparing the two shows items still in the property store but no longer known to the gatherer, a useful "deleted?" indicator. On Windows 10 the same tables live inside Windows.edb. See evidence of deleted files.