If you are uploading a file to Storage (manually or automatically), there's an option to upload it with the Public flag. The file can then be accessed publicly outside of Keboola Connection.
Only a minority of Keboola Connection users take advantage of this feature, and they do so in a very non-standard way (e.g., for HTML files). That's why we decided to deprecate it. Also, the new File Storage we have prepared (Azure Blob Storage) doesn't support public File Uploads, and we want to make this behavior consistent across all supported File Storage Backends.
The option to create Public Files from the UI has been removed (effective with the publication of this post).
The option to create Public Files via an API will be removed in about three months, by the end of June, 2020.
An alternative solution could be the AWS S3 Writer component, but we don't recommend relying on Public Files at all. Not even outside of Keboola Connection.