This question already has an answer here:
- Block error on CMI 5 answers
I have created some blocks of a specific type, in Drupal 8, and I want to import them into the cloned instance.
There is no core import feature available. How can I achieve the task?
They don't get imported by the configuration synchronization; if you try, you will get the error
This block is broken or missing. You may be missing content or you might need to enable the original module.
and no listing in custom block library.