webforms – How do I include composer.libraries.json in root composer.json without using the wikimedia/composer-merge-plugin plugin?

In the recent update to Composer 2.0 the advice is to get rid of the wikimedia/composer-merge-plugin, which was even removed from the dependencies of Drupal core.

There is documentation on how to include custom module’s composer.json in the root composer.json, for example Managing dependencies for a custom project, but I cannot find documentation on how to include composer.libraries.json in the root composer.json.

Can anyone explain how to get the Webform module compatible with Composer 2.0?