We are not actually using AEM Experience Fragments, but there are frequent error messages occurring during use on the author servers
saying that " *ERROR* [EventAdminAsyncThread #1] com.adobe.cq.xf.impl.adobetarget.TargetVariationModificationListener Cannot derive user name for bundle com.adobe.cq.cq-experience-fragments  and sub service experience-fragments-service". I can reproduce this by doing a Move Page but there are many other occurrences also.
So even though we don't use the Experience Fragments, maybe some of the feature's code gets exercised nonetheless?
I want to clean up the logs, so in the staging environment, I added a user mapping via the system console configmgr and the error messages went away.
For the production environment, I am not allowed to make changes directly via the AEM Console ConfigMgr so I have to create "conf" files in the code base instead. But when I added the user mapping via OSGi conf files, it seemed to be installed o.k. but didn't show up in the system console configmgr and the error messages did not go away. Here are the logs showing no errors during deployment of the code with the new conf files.
So it seems that subsequently the configuration gets overwritten or overruled somehow. (There are a few other Experience Fragment user mappings already present. ) Maybe because Experience Fragments is an internal feature and I'm not supposed to try altering its config via conf files.???
Any ideas on how I can get rid of the error messages. ?