This module depends on the unsupported responsive_image module

This module depends on the unsupported responsive_image module.

I do not think this is correct. The module's .info file lists drupal:responsive_image as a dependency which is a valid core module: https://git.drupalcode.org/project/drupal/-/tree/11.x/core/modules/respo... not the contrib module with the same machine name you linked to. If this module used the contrib module the .info file would list responsive_image:responsive_image.