Source

File: wp-includes/blocks.php

function filter_block_kses_value( $value, $allowed_html, $allowed_protocols = array() ) {
	if ( is_array( $value ) ) {
		foreach ( $value as $key => $inner_value ) {
			$filtered_key   = filter_block_kses_value( $key, $allowed_html, $allowed_protocols );
			$filtered_value = filter_block_kses_value( $inner_value, $allowed_html, $allowed_protocols );

			if ( $filtered_key !== $key ) {
				unset( $value[ $key ] );
			}

			$value[ $filtered_key ] = $filtered_value;
		}
	} elseif ( is_string( $value ) ) {
		return wp_kses( $value, $allowed_html, $allowed_protocols );
	}

	return $value;
}