Synthax change? Latest updates broke some functions

After full upgrade I noticed a couple of isolated code bits on a couple of rendered html pages:

We removed the overridding of the old markdown_extra system configuration setting. You just need to make sure you have:

markdown:
  extra: true

In your user/config/system.yaml

ok, I guess the point had been forgotten when repackaging skeletons.
Everything fine now, thanks!