Package phpunit/phpunit-mock-objects is abandoned

AT 3.1 on D8.6.13 and some earlier versions of D8.x on PHP 7.2

Recently when requiring AT 3.1 on new D8.6.13 and .12 (and possibly earlier D8.x) sites, and when updating earlier D8.x sites with AT 2.1, I get "Package phpunit/phpunit-mock-objects is abandoned, you should avoid using it. No replacement was suggested."

I see a recent article "Package phpunit/phpunit-mock-objects is abandoned" at https://www.drupal.org/project/drupal/issues/3033761 and it points to a year-old, still ongoing thread [PP-1] Support PHPUnit 7 in Drupal 8 at https://www.drupal.org/project/drupal/issues/2950132.

There were some general comments about core. I don't know if that complaint from my older site updates was from core or AT 2.1, but on new D8.6.13 sites I only get that complaint when I require AT 3.1.

D:\siteroot>composer require drupal/adaptivetheme
Using version ^3.1 for drupal/adaptivetheme
./composer.json has been updated
> DrupalProject\composer\ScriptHandler::checkComposerVersion
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 1 install, 0 updates, 0 removals
- Installing drupal/adaptivetheme (3.1.0): Loading from cache
Package phpunit/phpunit-mock-objects is abandoned, you should avoid using it. No replacement was suggested.
Writing lock file
Generating autoload files
> DrupalProject\composer\ScriptHandler::createRequiredFiles

I am not (yet?) enough of a Drupal developer to dig into the source code and get it to use a supported equivalent.