Pretty much what the title says. When assembling the list of dependencies, the site exporter assumes that anything which isn't a core extension is in the drupal vendor namespace.
Not always an assumption that holds, and it both confuses people and potentially makes extra work for them.
Ask Composer to get the proper package name. This will be a performance hit, but I think it's worthwhile for the accuracy. Exporting a site is not performance-sensitive anyway.
If the package name can't be determined, then assume the prefix is drupal.
Show commandsStart within a Git clone of the project using the version control instructions.
Or, if you do not have SSH keys set up on git.drupalcode.org:
changes
Comments
Comment #3
phenaproximaComment #4
phenaproximaComment #6
phenaproxima@antiorario and I manually tested this in Slack over DM and he confirmed that this works as intended. Merged, then, into 2.x and cherry-picked to 2.1.x.