Most modules however will have to remove deprecated code to be compatible with Drupal 9. Therefore they will not able to be compatible with all versions of Drupal 8.
For example a module that is compatible with Drupal 8 versions after Drupal 8.8.0 and also Drupal 9 will need a info.yml file like this:
name: My Module
type: module
core_version_requirement: ^8.8 || ^9
Closed: works as designed
2.0
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Thanks! Going to prefer deprecating Drupal 8. Keep up the contributions! Really appreciate your eyes here.