WP File Manager

Name	Action
..
block.json	Edit
editor-rtl.css	Edit
editor-rtl.min.css	Edit
editor.css	Edit
editor.min.css	Edit

Editing: block.json

{ "$schema": "https://schemas.wp.org/trunk/block.json", "apiVersion": 3, "name": "core/html", "title": "Custom HTML", "category": "widgets", "description": "Add custom HTML code and preview it as you edit.", "keywords": [ "embed" ], "textdomain": "default", "attributes": { "content": { "type": "string", "source": "raw" } }, "supports": { "customClassName": false, "className": false, "html": false, "interactivity": { "clientNavigation": true } }, "editorStyle": "wp-block-html-editor" }