WordPress at a glance
function is not described

wp_lazy_loading_enabled() WP 5.5.0

Determines whether to add the loading attribute to the specified tag in the specified context.

Hooks from the function
Return

true|false. Whether to add the attribute.

Usage

wp_lazy_loading_enabled( $tag_name, $context );
$tag_name(string) (required)
The tag name.
$context(string) (required)
Additional context, like the current filter name or the function name from where this was called.

Changelog

Since 5.5.0 Introduced.
Since 5.7.0 Now returns true by default for iframe tags.

Code of wp_lazy_loading_enabled() WP 5.7

<?php
function wp_lazy_loading_enabled( $tag_name, $context ) {
	// By default add to all 'img' and 'iframe' tags.
	// See https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-loading
	// See https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-loading
	$default = ( 'img' === $tag_name || 'iframe' === $tag_name );

	/**
	 * Filters whether to add the `loading` attribute to the specified tag in the specified context.
	 *
	 * @since 5.5.0
	 *
	 * @param bool   $default  Default value.
	 * @param string $tag_name The tag name.
	 * @param string $context  Additional context, like the current filter name
	 *                         or the function name from where this was called.
	 */
	return (bool) apply_filters( 'wp_lazy_loading_enabled', $default, $tag_name, $context );
}