I'm currently in the process of composerizing a quite old project where I ran into some strange module versions, which seem to have been packaged by drupal, ie.
# Information added by Drupal.org packaging script on 2019-03-28 version: '8.x-3.0-beta1+54-dev' core: '8.x' project: 'field_group' datestamp: 1553812385
# Information added by Drupal.org packaging script on 2017-03-13 version: '8.x-1.1+1-dev' core: '8.x' project: 'login_emailusername' datestamp: 1489402385
In the case of login_emailusername, it turned out that the code of the project is identical to 8.x-1.1 plus 1 follow-up commit from dev, and so could be brought into the project via composer as:
However, I wonder how these modules were "packaged" in these versions, because they don't seem to exist. Maybe someone has an idea? Might this be complete custom syntax or where they maybe imported via drush:make?