Wikimetrics backup should warn about symlinks pointing out of '/var/lib/wikimetrics'.
The '/var/lib/wikimetrics' is the directory that holds all public reports for wikimetrics, this directory is created by puppet.
Within that directory there are symlinks that give a more friendly name to reports, for example: "/NewlyRegistered/enwiki.json" might point to a file that just has an id like "/12345/full.report.json".
Now, the target of any symlink (the "12345/full_report.json") should be located inside the /var/lib/wikimetrics directory, if there are symlinks to paths located outside the directory backup script should log an error.
The backup script does not de-reference directories.