HTTP status codes / 1xx — Informational
WebDAV: the server accepted the request but has not completed it yet.
A WebDAV interim response telling the client the server is still working and the connection should not be treated as dead. Deprecated in practice and rarely seen outside legacy WebDAV stacks.
If you see 102 outside WebDAV, an intermediary is probably misbehaving.
The fastest way to pin down a 102 is to reproduce the exact request and inspect what actually went over the wire — status, headers, timing and body, without your app code in the way. That is what an API client is for; ReqPad does it from your phone, with every request saved to history.
100 Continue · 101 Switching Protocols · 103 Early Hints — or the full reference.
Build the request, send it, read status + headers + timing — on your iPhone. Free to start.