The heading level dropdown in the Heading block is powered by the HeadingLevelDropdown component. This component accepts and options parameter that allows you to choose which levels are available in the dropdown. Unfortunately, there is no way to modify this options parameter from a Heading block.

Being able to modify the available levels is critical for heavily curated editing environments and block "governance".

Consider the following situations:

• You only want to allow h2, h3, and h4 in Media & Text blocks.
• You want to disable h1 on posts since the template already populates an h1 for the post title.
• You want to disable the usage of h5 and h6 across the whole site.
• etc.

Curating the available heading levels is currently not possible, but it should be easy to implement using an additional attribute for the Heading block. Developers can then modify this attribute as they need, either directly in theme patterns and templates or via block filters like blocks.registerBlockType or register_block_type_args.

Current functionality	Goal

Should the mechanism be added to Heading blocks, we should explore similar mechanisms for other blocks with level dropdowns, like Site Title, Post Title, etc.