where can I find user_migrate module

Updating Drupal core, and I am getting a user warning:

      “The following module is missing from the file system: user_migrate

Searches of the module pages do not turn up this particular module, and I can’t complete the update without it.  

Where else should I look?

Thanks in advance!

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/22/feed