Pathauto and forum paths I can generate urls to forum topics fine, but pathauto appears to be stubbornly refusing to generate urls for Forums and containers no matter what patterns I try to use.

I even tried to alias them in core alias - as suggested for Drupal 7 here -  but aside from the fact that the pages then returned 404 results I will probably have users adding forums in the future so really need to be in a position to generate them. 

I want my forum urls to be of the form /private/discussion/forum-name and I would like to be able to have my container point to /private/discussion and see a list of the available forums there. Or at least alias the main forum output page.
I believe this is due to the issue reported here: https://www.drupal.org/project/drupal/issues/2010132. See the patch in comment #107 for a patch.

I've confirmed that the patch applies to the current Drupal 8.4 branch, the tests pass, and the aliases get generated as expected.