This API extension create custom PayPal paymnet method with code vsfpaypal your Magento 2 instance. It use develodesign/m2-paypal-payment composer module so you have to install it in your Magento 2.2.x instance.
composer config repositories.develodesign vcs https://github.com/develodesign/m2-paypal-payment.git
composer require develodesign/m2-paypal-payment:dev-master
bin/magento module:enable --all