Summary

gog calendar update writes events with timezone labels normalized to Etc/GMT-2 instead of preserving named IANA zones like Europe/Rome.

The actual instant is correct, but timezone semantics are degraded (important for travel events and editor UX consistency).

Environment

• gog version: 0.11.0 (Homebrew)
• OS: macOS Darwin 25.3.0 (arm64)
• Account/calendar: Google Calendar shared calendar

Repro

1. Create/update a calendar event with explicit cross-timezone start/end via gog:

gog calendar update <calendarId> <eventId> \
  --from 2026-08-13T13:40:00+02:00 \
  --to   2026-08-13T17:00:00-04:00 \
  --no-input --json

2. Fetch event:

gog calendar event <calendarId> <eventId> --json

Actual

Returned event timezone fields show:

• start.timeZone: Etc/GMT-2
• end.timeZone: America/New_York

Expected

When a named IANA zone is intended (e.g. Europe/Rome), preserve that zone name in event timezone metadata rather than canonicalizing to Etc/GMT-2.

Why this matters

• Calendar UI consistency: users expect Europe/Rome in timezone editor.
• DST and human readability are clearer with named zones.

Notes

• Creating/editing same event via Google Calendar web UI can preserve named zones as expected.
• This appears to be a gog write/update behavior, not a Google Calendar rendering issue.