Add custom block to editor

Hi,

I read the docs, but I didn't figured out how to add a custom block to editor, like a simple Google Maps iframe.
Is there a way to do this using Plain Text Editor?

Thank you!

Start by reviewing the editor documentation and the Plain Text Editor integration mentioned in the issue. Determine whether a custom block such as a Google Maps iframe is supported, where that capability would be configured, and what documentation or behavior would demonstrate that the request is complete.

Written by the indexing model from the issue text.