# Magento 2: Composer update / install is no longer copying magento2-base structure

I've got this strange problem I ran into only since recently.

Usually, when I got a new or existing project and I run composer install or composer update, composer will automatically copy (map) the contents of magento2-base to my project root. So magento2-base/lib gets copied to /lib and magento2-base/app/bootstrap.php gets copied to /app/bootstrap.php and so on...

But for some reason composer is not doing this anymore. Does anyone has any clue on how this can happen? I'm experiencing this issue all of a sudden since last Friday.

Found it! Turned out in a previous commit I accidentally removed the following from my composer.json-file:
"extra": {

Turns out that Magento uses this variable to determine if mapped folders in vendor modules' composer.json files are allowed to be copied (if they don't already exist).