>If they built their app differently, such as using a temporary directory rather than building it in tree in the release path, they could've used staged builds to cache their steps in docker

Can you explain this just a bit more, please?

I was just reading the two articles you linked today, and your comment seems there is some piece of insight that's missing.

If you search the multi-stage build article for "cache" the only hits are related to not using cache.

What should I do if I want to leverage the cache as much as possible in a multi stage build?