edlp_d8/core/modules/layout_discovery/layout_discovery.install

<?php

/**
 * @file
 * Install, update, and uninstall functions for the Layout Discovery module.
 */

/**
 * Implements hook_requirements().
 */
function layout_discovery_requirements($phase) {
  $requirements = [];
  if ($phase === 'install') {
    if (\Drupal::moduleHandler()->moduleExists('layout_plugin')) {
      $requirements['layout_discovery'] = [
        'description' => t('Layout Discovery cannot be installed because the Layout Plugin module is installed and incompatible.'),
        'severity' => REQUIREMENT_ERROR,
      ];
    }
  }
  return $requirements;
}