Should drush configuration export automatically update core.extension.yml? The Drupal 8 documentation seems to be lacking in regards to the core.extension.yml file, so I'm a little confused on the right way of updating it. 


Should drush be populating it on config export, or are you supposed to manually update it?  
Do I need to move it from core to my config/sync folder, or leave it in core? 


My file's contents are this, even though I have a handful of modules enabled on the site and have exported my config numerous times: 

module: {}
theme: {}
profile: ''


On the site I am exporting from (site a) I am using composer to download modules and drush en to enable them, then drush cex to export the configuration to my sync folder. When I copy the sync folder contents over site b and import via drush cim I run into errors that the modules are not installed / enabled. Manually enabling each module then re-importing was successful. 

Both sites are 8.3.7.
I think that the problem comes from where you have the config files, to be sure that they are really in the config/sync folder go to check if you have this following line in the settings.php file:

$config_directories = array(CONFIG_SYNC_DIRECTORY =&gt; 'config/sync');


Keep in mind that this line will have the location of the site configuration files.

Each time you use the drush cex or drush cex sync command the core.extension.yml file will be updated (if needed) with the actual modules (and others) configuration.