It's a metapackage for the source code repository.
Swissuplabs and Argento customers get access to Swissuplabs composer repository. If you want to install module via composer then please add Swissuplabs repo to your composer:
composer config repositories.ci.swissuplabs.com composer https://ci.swissuplabs.com/api/packages.jsonFor next steps go to http://docs.swissuplabs.com/m2/extensions/easyflags/installation/composer/
In case you don't have Swissuplabs/Argento account and don't want to create one. It is not a problem. You still can use this module. Just follow commands below:
cd <magento_root>
composer config repositories.swissup composer https://docs.swissuplabs.com/packages/
composer require swissup/easyflags
bin/magento module:enable Swissup_Core Swissup_Easyflags
bin/magento setup:upgrade