render_block_data filter-hook . WP 5.1.0

Filters the block being rendered in render_block(), before it's processed.

Usage

add_filter( 'render_block_data', 'filter_function_name_837', 10, 2 );
function filter_function_name_837( $block, $source_block ){
	// filter...

	return $block;
}

$block(array)

The block being rendered.

$source_block(array)

An un-modified copy of $block, as it appeared in the source content.

Where the hook is called

$block = apply_filters( 'render_block_data', $block, $source_block );

Where the hook is used (in WP core)