Add content to the WordPress viewpost post overview/list column

add-view-post-overview-column_content.php

<?php
/**
 * add_view_post_overview_column_content.
 *
 * Add content to the viewpost post overview/list column.
 *
 * @see https://since1979.dev/___/
 * @uses get_permalink() https://developer.wordpress.org/reference/functions/get_permalink/
 * @uses get_the_ID() https://developer.wordpress.org/reference/functions/get_the_id/
 */
function add_view_post_overview_column_content($column)
{
    if ($column !== 'viewpost') {
        return;
    }

    echo '<a href="' . get_permalink(get_the_ID()) . '" target="_blank">View post</a>';
}

/**
 * Hook: manage_posts_custom_column.
 *
 * @uses add_action() https://developer.wordpress.org/reference/functions/add_action/
 * @uses manage_posts_custom_column https://developer.wordpress.org/reference/hooks/manage_posts_custom_column/
 */
add_action('manage_posts_custom_column', 'add_view_post_overview_column_content');
?>