For the past few years we have not dumped private tables at all; they would
not be accessible to the public in any case, and they do not suffice as a
backup in case of catastrophic failure.
We are therefore removing the feature to dump private tables along with
public tables in a dump run. Anyone who wishes to use the dump scripts in
our python repo to dump privat tables in their wiki will need to create a
separate dumps configuration file and tables yaml file describing which
tables to dump and where to put them, as a separate dump run.
This change will be committed by April 20, 2020, in time for the second
dump run of the month.
Note that this does not impact the actual output of the Wikimedia SQL/XML
dumps at all, since we have not been dumping private tables since late 2016.
See T249508 to follow along.
Ariel