Complete rewrite in code which is more "understandable" to me. Exact same code as core code found `post_submit_meta_box();` here: `/wp-admin/includes/meta-boxes.php`

meta-box-publish.php

/**
 * Displays post submit form fields.
 *
 * @since 2.7.0
 *
 * @global string $action
 *
 * @param WP_Post $post Current post object.
 * @param array $args {
 *     Array of arguments for building the post submit meta box.
 *
 * @type string $id Meta box ID.
 * @type string $title Meta box title.
 * @type callable $callback Meta box display callback.
 * @type array $args Extra meta box arguments.
 * }
 */
public function meta_box_actions( $post, $args = array() ) {
	global $action;

	$post_type        = $post->post_type;
	$post_type_object = get_post_type_object( $post_type );
	$can_publish      = current_user_can( $post_type_object->cap->publish_posts );

	// BoF #submitpost .submitbox
	echo '<div class="submitbox" id="submitpost">' . PHP_EOL;

	// BoF #minor-publishing
	echo '<div id="minor-publishing">' . PHP_EOL;

	// Hidden submit button early on so that the browser chooses the right button when form is submitted with Return key
	echo '<div style="display:none;">' . PHP_EOL;
	submit_button( __( 'Save' ), 'button', 'save' );
	echo '</div>' . PHP_EOL;

	// BoF #minor-publishing-actions
	echo '<div id="minor-publishing-actions">' . PHP_EOL;

	// BoF #save-action
	echo '<div id="save-action">' . PHP_EOL;

	if ( $post->post_status != 'publish' && $post->post_status != 'future' && $post->post_status != 'pending' ) {

		if ( $post->post_status == 'private' ) {
			$style = 'style="display:none;"';
		} else {
			$style = '';
		}

		echo '<input ' . $style . ' type="submit" name="save" id="save-post" value="' . esc_attr( 'Save Draft' ) . '" class="button" />' . PHP_EOL;
		echo '<span class="spinner"></span>' . PHP_EOL;

	} elseif ( $post->post_status == 'pending' && $can_publish ) {

		echo '<input type="submit" name="save" id="save-post" value="' . esc_attr( 'Save as Pending' ) . '" class="button" />' . PHP_EOL;
		echo '<span class="spinner"></span>' . PHP_EOL;

	}

	echo '</div><!-- end #save-action -->' . PHP_EOL;
	// EoF #save-action

	if ( is_post_type_viewable( $post_type_object ) ) {

		// BoF #preview-action
		echo '<div id="preview-action">' . PHP_EOL;

		$preview_link = esc_url( get_preview_post_link( $post ) );

		if ( $post->post_status == 'publish' ) {
			$preview_button = 'Preview Changes';
		} else {
			$preview_button = 'Preview';
		}

		echo '<a class="preview button" href="' . $preview_link . '" target="wp-preview-' . (int) $post->ID . '" id="post-preview">' . $preview_button . '</a>' . PHP_EOL;
		echo '<input type="hidden" name="wp-preview" id="wp-preview" value="" />' . PHP_EOL;
		echo '</div><!-- end #preview-action -->' . PHP_EOL;
		// EoF #preview-action

	}// public post type

	/**
	 * Fires before the post time/date setting in the Publish meta box.
	 *
	 * @since 4.4.0
	 *
	 * @param WP_Post $post WP_Post object for the current post.
	 */
	do_action( 'post_submitbox_minor_actions', $post );

	echo '<div class="clear"></div>' . PHP_EOL;

	echo '</div><!-- #minor-publishing-actions -->' . PHP_EOL;
	// EoF #minor-publishing-actions

	// BoF #misc-publishing-actions
	echo '<div id="misc-publishing-actions">' . PHP_EOL;

	// BoF .misc-pub-section .misc-pub-post-status
	echo '<div class="misc-pub-section misc-pub-post-status">' . PHP_EOL;

	echo '<label for="post_status">Status:</label>' . PHP_EOL;

	echo '<span id="post-status-display">' . PHP_EOL;

	switch ( $post->post_status ) {
		case 'private':
			_e( 'Privately Published' );
			break;
		case 'publish':
			_e( 'Published' );
			break;
		case 'future':
			_e( 'Scheduled' );
			break;
		case 'pending':
			_e( 'Pending Review' );
			break;
		case 'draft':
		case 'auto-draft':
			_e( 'Draft' );
			break;
	}

	echo '</span>' . PHP_EOL;

	if ( $post->post_status == 'publish' || $post->post_status == 'private' || $can_publish ) {

		if ( $post->post_status == 'private' ) {
			$style = 'style="display:none"';
		} else {
			$style = '';
		}

		echo '<a href="#post_status" ' . $style . ' class="edit-post-status hide-if-no-js"><span aria-hidden="true">Edit</span> <span class="screen-reader-text">Edit status</span></a>' . PHP_EOL;

		// BoF #post-status-select .hide-if-js
		echo '<div id="post-status-select" class="hide-if-js">' . PHP_EOL;

		echo '<input type="hidden" name="hidden_post_status" id="hidden_post_status" value="' . esc_attr( $post->post_status ) . '" />' . PHP_EOL;

		echo '<select name="post_status" id="post_status">' . PHP_EOL;

		if ( $post->post_status == 'publish' ) {
			echo '<option ' . selected( $post->post_status, 'publish', false ) . ' value="publish">Published</option>' . PHP_EOL;
		} elseif ( $post->post_status == 'private' ) {
			echo '<option ' . selected( $post->post_status, 'private', false ) . ' value="publish">Privately Published</option>' . PHP_EOL;
		} elseif ( $post->post_status == 'future' ) {
			echo '<option ' . selected( $post->post_status, 'future', false ) . ' value="future">Scheduled</option>' . PHP_EOL;
		}

		echo '<option ' . selected( $post->post_status, 'pending', false ) . ' value="pending">Pending Review</option>' . PHP_EOL;

		if ( $post->post_status == 'auto-draft' ) {
			echo '<option ' . selected( $post->post_status, 'auto-draft', false ) . ' value="draft">Draft</option>' . PHP_EOL;
		} else {
			echo '<option ' . selected( $post->post_status, 'draft', false ) . ' value="draft">Draft</option>' . PHP_EOL;
		}

		echo '</select>' . PHP_EOL;

		echo '<a href="#post_status" class="save-post-status hide-if-no-js button">OK</a>' . PHP_EOL;
		echo '<a href="#post_status" class="cancel-post-status hide-if-no-js button-cancel">Cancel</a>' . PHP_EOL;

		echo '</div><!-- end #post-status-select .hide-if-js -->' . PHP_EOL;
		// EoF #post-status-select .hide-if-js

	}

	echo '</div><!-- end .misc-pub-section .misc-pub-post-status -->' . PHP_EOL;
	// EoF .misc-pub-section .misc-pub-post-status

	// BoF #visibility .misc-pub-section .misc-pub-visibility
	echo '<div class="misc-pub-section misc-pub-visibility" id="visibility">' . PHP_EOL;

	echo 'Visibility: <span id="post-visibility-display">' . PHP_EOL;

	if ( $post->post_status == 'private' ) {
		$post->post_password = '';
		$visibility          = 'private';
		$visibility_trans    = __( 'Private' );
	} elseif ( ! empty( $post->post_password ) ) {
		$visibility       = 'password';
		$visibility_trans = __( 'Password protected' );
	} elseif ( $post_type == 'post' && is_sticky( $post->ID ) ) {
		$visibility       = 'public';
		$visibility_trans = __( 'Public, Sticky' );
	} else {
		$visibility       = 'public';
		$visibility_trans = __( 'Public' );
	}

	echo esc_html( $visibility_trans );

	echo '</span>' . PHP_EOL;

	if ( $can_publish ) {

		echo '<a href="#visibility" class="edit-visibility hide-if-no-js"><span aria-hidden="true">Edit</span> <span class="screen-reader-text">Edit visibility</span></a>' . PHP_EOL;

		// BoF #post-visibility-select .hide-if-js
		echo '<div id="post-visibility-select" class="hide-if-js">' . PHP_EOL;

		echo '<input type="hidden" name="hidden_post_password" id="hidden-post-password" value="'.esc_attr($post->post_password).'" />' . PHP_EOL;

		if ( $post_type == 'post' ) {
			echo '<input type="checkbox" style="display:none" name="hidden_post_sticky" id="hidden-post-sticky" value="sticky" ' . checked( is_sticky( $post->ID ), true, false ) . ' />' . PHP_EOL;
		}

		echo '<input type="hidden" name="hidden_post_visibility" id="hidden-post-visibility" value="' . esc_attr( $visibility ) . '" />' . PHP_EOL;
		echo '<input type="radio" name="visibility" id="visibility-radio-public" value="public" ' . checked( $visibility, 'public', false ) . ' /> <label for="visibility-radio-public" class="selectit">Public</label><br />' . PHP_EOL;

		if ( $post_type == 'post' && current_user_can( 'edit_others_posts' ) ) {
			echo '<span id="sticky-span"><input id="sticky" name="sticky" type="checkbox" value="sticky" ' . checked( is_sticky( $post->ID ), true, false ) . ' /> <label for="sticky" class="selectit">Stick this post to the front page</label><br /></span>' . PHP_EOL;
		}

		echo '<input type="radio" name="visibility" id="visibility-radio-password" value="password" ' . checked( $visibility, 'password', false ) . ' /> <label for="visibility-radio-password" class="selectit">Password protected</label><br />' . PHP_EOL;
		echo '<span id="password-span"><label for="post_password">Password:</label> <input type="text" name="post_password" id="post_password" value="' . esc_attr( $post->post_password ) . '"  maxlength="20" /><br /></span>' . PHP_EOL;
		echo '<input type="radio" name="visibility" id="visibility-radio-private" value="private" ' . checked( $visibility, 'private', false ) . ' /> <label for="visibility-radio-private" class="selectit">Private</label><br />' . PHP_EOL;

		echo '<p>' . PHP_EOL;
		echo '<a href="#visibility" class="save-post-visibility hide-if-no-js button">OK</a>' . PHP_EOL;
		echo '<a href="#visibility" class="cancel-post-visibility hide-if-no-js button-cancel">Cancel</a>' . PHP_EOL;
		echo '</p>' . PHP_EOL;

		echo '</div><!-- end #post-visibility-select .hide-if-js -->' . PHP_EOL;
		// RoF #post-visibility-select .hide-if-js

	}

	echo '</div><!-- #visibility .misc-pub-section .misc-pub-visibility -->' . PHP_EOL;
	// EoF #visibility .misc-pub-section .misc-pub-visibility

	/* translators: Publish box date format, see http://php.net/date */
	$datef = __( 'M j, Y @ H:i' );

	if ( $post->ID != 0 ) {

		if ( 'future' == $post->post_status ) { // scheduled for publishing at a future date
			$stamp = __( 'Scheduled for: <b>%1$s</b>' );
		} elseif ( $post->post_status == 'publish' || $post->post_status == 'private' ) { // already published
			$stamp = __( 'Published on: <b>%1$s</b>' );
		} elseif ( $post->post_date_gmt == '0000-00-00 00:00:00' ) { // draft, 1 or more saves, no date specified
			$stamp = __( 'Publish <b>immediately</b>' );
		} elseif ( time() < strtotime( $post->post_date_gmt . ' +0000' ) ) { // draft, 1 or more saves, future date specified
			$stamp = __( 'Schedule for: <b>%1$s</b>' );
		} else { // draft, 1 or more saves, date specified
			$stamp = __( 'Publish on: <b>%1$s</b>' );
		}

		$date = date_i18n( $datef, strtotime( $post->post_date ) );

	} else { // draft (no saves, and thus no date specified)

		$stamp = __( 'Publish <b>immediately</b>' );
		$date  = date_i18n( $datef, strtotime( current_time( 'mysql' ) ) );

	}

	if ( ! empty( $args['args']['revisions_count'] ) ) {
		$revisions_to_keep = wp_revisions_to_keep( $post );
	}

	// BoF .misc-pub-section .misc-pub-revisions
	echo '<div class="misc-pub-section misc-pub-revisions">' . PHP_EOL;

	if ( $revisions_to_keep > 0 && $revisions_to_keep <= $args['args']['revisions_count'] ) {

		echo '<span title="' . esc_attr( sprintf( __( 'Your site is configured to keep only the last %s revisions.' ), number_format_i18n( $revisions_to_keep ) ) ) . '">' . PHP_EOL;
		printf( __( 'Revisions: %s' ), '<b>' . number_format_i18n( $args['args']['revisions_count'] ) . '+</b>' );
		echo '</span>' . PHP_EOL;

	} else {

		printf( __( 'Revisions: %s' ), '<b>' . number_format_i18n( $args['args']['revisions_count'] ) . '</b>' );

	}

	echo ' <a class="hide-if-no-js" href="' . esc_url( get_edit_post_link( $args['args']['revision_id'] ) ) . '"><span aria-hidden="true">Browse</span> <span class="screen-reader-text">Browse revisions</span></a>' . PHP_EOL;

	echo '</div><!-- end .misc-pub-section .misc-pub-revisions -->' . PHP_EOL;
	// EoF .misc-pub-section .misc-pub-revisions

	if ( $can_publish ) {// Contributors don't get to choose the date of publish

		// BoF .misc-pub-section .curtime .misc-pub-curtime
		echo '<div class="misc-pub-section curtime misc-pub-curtime">' . PHP_EOL;

		echo '<span id="timestamp">' . sprintf( $stamp, $date ) . '</span>' . PHP_EOL;
		echo '<a href="#edit_timestamp" class="edit-timestamp hide-if-no-js"><span aria-hidden="true">Edit</span> <span class="screen-reader-text">Edit date and time</span></a>' . PHP_EOL;
		echo '<fieldset id="timestampdiv" class="hide-if-js">' . PHP_EOL;
		echo '<legend class="screen-reader-text">Date and time</legend>' . PHP_EOL;
		touch_time( ( $action === 'edit' ), 1 );
		echo '</fieldset>' . PHP_EOL;

		echo '</div><!-- end .misc-pub-section .curtime .misc-pub-curtime -->' . PHP_EOL;
		// EoF .misc-pub-section .curtime .misc-pub-curtime

	}

	/**
	 * Fires after the post time/date setting in the Publish meta box.
	 *
	 * @since 2.9.0
	 * @since 4.4.0 Added the `$post` parameter.
	 *
	 * @param WP_Post $post WP_Post object for the current post.
	 */
	do_action( 'post_submitbox_misc_actions', $post );

	echo '</div><!-- end #minor-publishing-actions -->' . PHP_EOL;
	// EoF #minor-publishing-actions

	echo '<div class="clear"></div>' . PHP_EOL;
	echo '</div><!-- end #minor-publishing -->' . PHP_EOL;
	// EoF #minor-publishing

	// BoF #major-publishing-actions
	echo '<div id="major-publishing-actions">' . PHP_EOL;

	/**
	 * Fires at the beginning of the publishing actions section of the Publish meta box.
	 *
	 * @since 2.7.0
	 */
	do_action( 'post_submitbox_start' );

	// BoF #delete-action
	echo '<div id="delete-action">' . PHP_EOL;

	if ( current_user_can( "delete_post", $post->ID ) ) {

		if ( ! EMPTY_TRASH_DAYS ) {
			$delete_text = 'Delete Permanently';
		} else {
			$delete_text = 'Move to Trash';
		}

		echo '<a class="submitdelete deletion" href="' . get_delete_post_link( $post->ID ) . '">' . $delete_text . '</a>' . PHP_EOL;
	}

	echo '</div><!-- end #delete-action -->' . PHP_EOL;
	// EoF #delete-action

	// BoF #publishing-action
	echo '<div id="publishing-action">' . PHP_EOL;

	echo '<span class="spinner"></span>' . PHP_EOL;

	if ( ! in_array( $post->post_status, array( 'publish', 'future', 'private' ) ) || 0 == $post->ID ) {

		if ( $can_publish ) {

			if ( ! empty( $post->post_date_gmt ) && time() < strtotime( $post->post_date_gmt . ' +0000' ) ) {

				echo '<input name="original_publish" type="hidden" id="original_publish" value="' . esc_attr( 'Schedule' ) . '" />' . PHP_EOL;
				submit_button( 'Schedule', 'primary button-large', 'publish', false );

			} else {

				echo '<input name="original_publish" type="hidden" id="original_publish" value="' . esc_attr( 'Publish' ) . '" />' . PHP_EOL;
				submit_button( 'Publish', 'primary button-large', 'publish', false );

			}

		} else {

			echo '<input name="original_publish" type="hidden" id="original_publish" value="' . esc_attr( 'Submit for Review' ) . '" />' . PHP_EOL;
			submit_button( 'Submit for Review', 'primary button-large', 'publish', false );

		}

	} else {

		echo '<input name="original_publish" type="hidden" id="original_publish" value="' . esc_attr( 'Update' ) . '" />' . PHP_EOL;
		echo '<input name="save" type="submit" class="button button-primary button-large" id="publish" value="' . esc_attr( 'Update' ) . '" />' . PHP_EOL;

	}

	echo '</div><!-- end #publishing-action -->' . PHP_EOL;
	// EoF #publishing-action

	echo '<div class="clear"></div>' . PHP_EOL;

	echo '</div><!-- end #major-publishing-actions -->' . PHP_EOL;
	// EoF #major-publishing-actions

	echo '</div><!-- end #submitpost .submitbox -->' . PHP_EOL;
	// EoF #submitpost .submitbox

}