WAMP environment.
Magento installation is ok, I can see frontend and backend with no issues.
However I noticed there is no theme folders, blank and luma, where they were supposed to be.
Blank and luma folders are only found at pub/static/frontend/Magento folder but not in app/design/frontend/Magento.
I found this issue while trying to create a new theme which will inherit from blank (thus noticing there is no blank or luma folder)