Overview
Settings, then Integrations, is where every App Store Connect account linked to this workspace lives.
App Store Connect
A connected account is named by the public seller name of the apps on that key, or by the label you gave it, always in uppercase. The key itself is never displayed, and neither are its Issuer or Key ID: they stay on Spek's servers.
Disconnect removes the stored credential. You can also revoke the key in App Store Connect, which takes effect immediately whatever Spek holds. Setting one up is covered in connect App Store Connect.
Common questions
Why can I not disconnect?
Changing a connection needs a role that allows it. The page says to contact an admin or editor when yours does not.
What happens to my drafts if I disconnect?
They stay. What stops is Spek's ability to read from or publish to that store account until you connect again.