FTP Files is designed to keep your information private. It does this by collecting very little information, using as few third party services as possible and end-to-end encrypting data when possible.
The servers your configure are shared between your different devices using iCloud if you have iCloud Keychain enabled.
The app collects usage data to determine the popularity of features and to detect user interactions causing confusion. This is done without recording personal information and without any details from your servers.
Usage data is recorded using TelemetryDeck.