Error in huge template - how to find the culprit?

thx, but that failed on missing filters.
In any case, I stripped out al for loops and found the problem.
The deployer had commented out list items, but did not leave any.
So:

foobar:

  • bar
  • baz
  • bor

was in the config as:

foobar:

- bar

- baz

- bor

which meant it wasn’t a list anymore, but null instead, and thus None in python…

Dick