Hi There!
 
Magento 2.0.4
 
1. I defined very simple, test custom theme that doesn't have any ancestors and files for now.
 
Only stuff in the folder are: 
- Media folder with theme preview image
- registration.php
- theme.xml
 
2. Then, attach it in admin panel to one of web sites. The web site has fr_FR locale set up.
3. Run setup:static-content:deploy fr_FR
4. Both themes luma and blank are re-generated for fr_FR in pub/static/frontend, but not my theme
 
Why is it so?
 
1. Lack of folder structure?
2. Lack for ancestor??
 
Any help much appriciated. Thanks!
 
Pete