WordPress at a glance
filter is not described

render_block filter-hook . WP 5.0.0

Filters the content of a single block.

Usage

add_filter( 'render_block', 'filter_function_name_3519', 10, 2 );
function filter_function_name_3519( $block_content, $block ){
	// filter...

	return $block_content;
}
$block_content(string)
The block content about to be appended.
$block(array)
The full block, including name and attributes.

Where the hook is called

render_block()
wp-includes/blocks.php 205
return apply_filters( 'render_block', $block_content, $block );

Where the hook is used (in WP core)

Does not used.