https://github.com/mongodb/mongo/blob/6c2169cc938d4ef1797782be934e6ce7c97fc21a/src/mongo/s/catalog/replset/sharding_catalog_client_impl.cpp#L1376

Example log snippet:

"... chunk operation commit failed: version 5|3||579382c09126d7bb74baac09 doesn't exist in namespacetest.foo ..."

There should be a space between namespace and test.foo for readability