ska-blocks blocks, such as Element and Text, have the ability to accept custom HTML attributes:
This allows to add things that the block editor may not support at the time, such as specifying aria- values, adding data- values, integrating with Alpine.js, adding schema markup and more.
Since attribute values can get long and it’s a little cramped in the block editor sidebar, there is a button to edit the attributes in a larger modal.
The clipboard icon allows to copy current attributes, and the value can be pasted to any other block, into the “Key…” or “Value…” input field and all the attributes from the clipboard will be added.