Add to wp-config.php:

define( 'DISALLOW_FILE_MODS', true );

Useful when managing plugin updates via Composer.

<?php
the_post_thumbnail( '', array( 'loading' => 'eager' ) );

<div class="blog-navigation"><?php posts_nav_link( ' ', 'Previous', 'Next' ); ?></div>

.blog-navigation {
	display: flex;
	justify-content: flex-start;
	padding: 1rem 0;

	a {
		@extend .button;
		@extend .button--primary;
	}

	// Ensures Next button is always right aligned, even when no Previous button
	a:last-of-type {
		margin-left: auto;
	}
}

Otherwise it falls back to echoing another menu (the first?) instead of nothing.

<?= wp_nav_menu( [ 'echo' => false, 'fallback_cb' => false, 'theme_location' => 'footer-2-a' ] ) ?: ''; ?>

<?php

$args = [ 'show_in_rest' => true ];

register_post_type( 'post-type-slug', $args );

You need to set the loading attribute to eager.

wp_get_attachment_image(
    $image_id,
    'full',
    false,
    [ 'loading' => 'eager' ], // Prevent image from being lazy loaded.
);

<?php

namespace NickDavis\AsyncExample;

const ASYNC_EXAMPLE = 'nd-async-example';

add_action( 'wp_enqueue_scripts', __NAMESPACE__ . '\enqueue_script' );
/**
 * Enqueues the async example script.
 *
 * @since v1.0.0
 */
function enqueue_script() {
	wp_enqueue_script( ASYNC_EXAMPLE, '//async.example.com', [], null, true );
}

add_filter( 'script_loader_tag', __NAMESPACE__ . '\add_async_attribute', 10, 2 );
/**
 * Add an aysnc attribute to an enqueued script.
 *
 * @url https://wordpress.stackexchange.com/a/198372
 *
 * @since v1.0.0
 *
 * @param string $tag Tag for the enqueued script.
 * @param string $handle The script's registered handle.
 * @return string Script tag for the enqueued script
 */
function add_async_attribute( $tag, $handle ) {
    // Just return the tag normally if this isn't one we want to async.
    if ( ASYNC_EXAMPLE !== $handle ) {
        return $tag;
    }

    return str_replace( ' src', ' async src', $tag );
}