Redo EFQ in rebuild_batch_fetch

I was trying to port #2392579: Rebuild should skip excluded bundles and, while in xmlsitemap_rebuild_batch_fetch(), I could see that PHPStorm was flagging the EFQ. Turns out that's been rewritten: https://www.drupal.org/node/1827278

Trouble is, I can't figure out how to get that code to run so I can test the ported patch as well as make the EFQ changes. When you go to the rebuild page in settings, it runs:

XmlSitemapRebuildForm.php - buildForm()
xmlsitemap.module - xmlsitemap_get_rebuildable_link_types()
xmlsitemap.module - xmlsitemap_get_link_info()

And within there, has this code:

if (!isset($info['xmlsitemap']['rebuild callback']) && !empty($info['base table']) && !empty($info['entity keys']['id']) && !empty($info['xmlsitemap']['process callback'])) {
  $info['xmlsitemap']['rebuild callback'] = 'xmlsitemap_rebuild_batch_fetch';
}

But I've tried tracing thru and just can't figure out what that code is all doing and how to get it to run the function that needs fixing.

If anyone has any repro steps to make that function run, I'd be glad to port that patch as well as rewrite the EFQ.