Modal.js not present in 5

The modal.js file is present in the Bootstrap 5 theme at the paths dist/bootstrap/{version}/js/dist and dist/bootstrap/{version}/js/src. And then you can add it wherever you want and use it according to the official Bootstrap 5 documentation.

I was talking about the bridge. - See image attached.

But ok, I ended up https://www.drupal.org/project/bootstrap4_modal → and patch / adapt for Drupal 10

Unfortunately, this is not available in this theme.
But this is a good idea of where to develop this theme in the future.