Get only errors and warnings about a snapshot

When you run a snapshot, some or many warnings are displayed like this one:
Ignored error when processing “etc/s6/current/run-image/service/s6-svscan-log/fifo”: unknown or unsupported entry type
We can miss some of them, particularly if the kopia command belongs to a script. It could be important to know that some particular files have been excluded from a snapshot
Is there a command or log extract to get all the errors and warnings about one snapshot ?