In __session_open_cursor, we have the following:

    if (config != NULL && (WT_PREFIX_MATCH(uri, "backup:") || to_dup != NULL))
        __wt_verbose(session, WT_VERB_BACKUP, "Backup cursor config \"%s\"", config);

This requires a strncmp for every cursor open with a configuration. This would be better off in __session_open_cursor_int, at the point where we already know we have a URI that starts with "backup:".
 
In WT-12153, "strncmp" has been noticed on the profile, it could be that some of this is attributed to this call.  But for cursors that are cached and reopened, this code won't be executed.