$ composer require 'drupal/avatars_gravatar:2.x-dev'
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- The requested package drupal/avatars_gravatar 2.x-dev exists as drupal/avatars_gravatar[1.0.0, 1.0.0-beta5, 1.0.0-beta4, 1.0.0-beta3, 1.0.0-beta2, 1.0.0-beta1, 1.0.0-alpha5, 1.0.0-alpha4, 1.0.0-alpha3, dev-1.x, 1.x-dev] but these are rejected by your constraint.
Installation failed, reverting ./composer.json to its original content.
I tried clearing my composer caches - no help. The really weird thing is that the only version should be '2.x-dev', none of those 1.x versions should exist at all.
Could this be a problem with the Drupal.org composer end point? Is maybe something else somewhere in the composer eco-system calling itself 'drupal/avatars_gravatar'?