Source

File: wp-admin/includes/misc.php

function wp_print_plugin_file_tree( $tree, $label = '', $level = 2, $size = 1, $index = 1 ) {
	global $file, $plugin;
	if ( is_array( $tree ) ) {
		$index = 0;
		$size  = count( $tree );
		foreach ( $tree as $label => $plugin_file ) :
			$index++;
			if ( ! is_array( $plugin_file ) ) {
				wp_print_plugin_file_tree( $plugin_file, $label, $level, $index, $size );
				continue;
			}
			?>
			<li role="treeitem" aria-expanded="true" tabindex="-1"
				aria-level="<?php echo esc_attr( $level ); ?>"
				aria-setsize="<?php echo esc_attr( $size ); ?>"
				aria-posinset="<?php echo esc_attr( $index ); ?>">
				<span class="folder-label"><?php echo esc_html( $label ); ?> <span class="screen-reader-text"><?php _e( 'folder' ); ?></span><span aria-hidden="true" class="icon"></span></span>
				<ul role="group" class="tree-folder"><?php wp_print_plugin_file_tree( $plugin_file, '', $level + 1, $index, $size ); ?></ul>
			</li>
			<?php
		endforeach;
	} else {
		$url = add_query_arg(
			array(
				'file'   => rawurlencode( $tree ),
				'plugin' => rawurlencode( $plugin ),
			),
			self_admin_url( 'plugin-editor.php' )
		);
		?>
		<li role="none" class="<?php echo esc_attr( $file === $tree ? 'current-file' : '' ); ?>">
			<a role="treeitem" tabindex="<?php echo esc_attr( $file === $tree ? '0' : '-1' ); ?>"
				href="<?php echo esc_url( $url ); ?>"
				aria-level="<?php echo esc_attr( $level ); ?>"
				aria-setsize="<?php echo esc_attr( $size ); ?>"
				aria-posinset="<?php echo esc_attr( $index ); ?>">
				<?php
				if ( $file === $tree ) {
					echo '<span class="notice notice-info">' . esc_html( $label ) . '</span>';
				} else {
					echo esc_html( $label );
				}
				?>
			</a>
		</li>
		<?php
	}
}