We'll create fresh WordPress site with Block Data Attribute installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This plugin designed with extensibility in mind for data that should be associated with a particular block type but need not have any defined meaning. data-*
attributes will allow you to store extra information on different Gutenberg blocks, without other hacks such as non-standard attributes, appending properties on DOM, or modifying a block as HTML which will throw a block validation error when opening the post edit page once again.