This is used in the GetClaims and GetEntities api modules.
The current DataModelSerialization library does not
support ungrouped lists currently, do we could deprecate
this now to give people warning.
I have added logging to the feature use @ https://logstash.wikimedia.org/#dashboard/temp/AU63scYgs2oZVZyjfrS2
In roughly 4 days only 50 calls using the parameter were made, all by 1 IP user.