The documentation at https://docs.cryptpad.org/en/admin_guide/customization.html states that you should add the AppConfig.loginSalt configuration option to www/common/application_config.js. This file does not exist, and seems like an odd location.
I assumed that customize/application_config.js would be the right place. But as pointed out in https://forum.cryptpad.org/d/207-diagnostics-checkup-not-safe/4, that is not a safe place to put it.
So what is the correct location of the AppConfig.loginSalt configuration value?