cpython/Misc/NEWS.d/next/Library/2021-02-19-22-24-33.bpo-43265.MyAzCH.rst

Improve :meth:`sqlite3.Connection.backup` error handling. The error message
for non-existant target database names is now ``unknown database <database
name>`` instead of ``SQL logic error``. Patch by Erlend E. Aasland.