Problem when i want use ckeditor_codemirror with composer/installers:2.*

Thanks for reporting -- If you want to provide an MR you can take a look at how we addressed this in 3.0.x here: 🐛 Requires old version of composer installers in composer.libraries.json Fixed . Otherwise I'll just backport those changes at some point.

Sorry, I don't see that they fix it in 2.5-beta1...

https://git.drupalcode.org/project/ckeditor_codemirror/-/commit/f7b8a7ad...

That's correct -- 🐛 Requires old version of composer installers in composer.libraries.json Fixed has only been applied to the 3.0.x branch. Since you assigned this issue to yourself I was assuming you were working on an MR for the 8.x-2.x branch. That is fine if so. But if not please unassign yourself and I'll just backport the 3.0.x commit.