GitLab

also left comments on this for this test and python datasrc test
for reference for others

still support no report mode.

And a minor cleanup in the code

And update doc and do a bit of style cleanup

And update doc and do a bit of style cleanup

There were some small changes in the behaviour of MasterLoader as a
result of review, this is update do ZoneLoader and its tests to
incorporate that.

Some of the code can be shared between the variants, saving some code.

After the rebase on top of working 2377. The most significant - don't
access updater if it doesn't exist.