WordPress at a glance
filter is not described

block_parser_class filter-hook . WP 5.0.0

Filter to allow plugins to replace the server-side block parser

Usage

add_filter( 'block_parser_class', 'filter_function_name_4460' );
function filter_function_name_4460( $parser_class ){
	// filter...

	return $parser_class;
}
$parser_class(string)
Name of block parser class.

Where the hook is called

parse_blocks()
wp-includes/blocks.php 224
$parser_class = apply_filters( 'block_parser_class', 'WP_Block_Parser' );

Where the hook is used (in WP core)

Does not used.