This website is open source, you can fork it on Boomla.
Here is a secret not stored on the filesystem of this website:
gtwyDzRo8aTx4RGRtToMqSdSh7ndeFHb
You will not gain access to the above secret by forking this website.
Keep the secret keys on another branch of the same website, on a subdomain named db-fj9h9wdw. In this case, the website is stored on secret-keys.boomla.net, while the secret keys are stored on db-fj9h9wdw.secret-keys.boomla.net.
The public website (secret-keys.boomla.net) is open source.
The branch holding the secret keys (db-fj9h9wdw.secret-keys.boomla.net) is closed source.