User warning: The following theme is missing from the file system: classy

Holy theme ver. 3 have base theme starterkit_theme

If it is missing, it can be installed:
drush theme:enable THEME_NAME
drush theme:enable starterkit_theme

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If need classy in D9, D10:
https://www.drupal.org/project/classy →

Thanks for your reply. Theme 'classy' is not available for Drupal 11 so for now I had to comment this line:

{{ attach_library('classy/node') }}

in these twig files:

• web/themes/contrib/holy/templates/contentnode--full.html.twig
• web/themes/contrib/holy/templates/contentnode--teaser.html.twig

OK.

It must be put there:
{{ attach_library('starterkit_theme/node') }}

It will be fixed soon. Thanks.

Here is patch.

Thanks for quick fix! It works.

It will be fixed next release.