Not in the iPhone app, not in the plugins. Everything there is to know fits in five boxes.
STAB for iPhoneNothing leaves your phone. No sign-in, no analytics, no internet. It talks to a K.O. II over the cable, and only to it.
Mac and WindowsThe plugin checks your licence key with Gumroad once, then works offline. Nothing about how you use it is sent.
The iPhone waiting listIf you join it, Gumroad holds your email address so I can tell you when the app is out. One email, with an unsubscribe in it.
This siteA visit counter with no cookies (Cloudflare). A message you send reaches only me, to answer it.
PaymentsHandled by Apple on iPhone and by Gumroad on desktop. I never see your card.