The previous commit documented the clock-zone requirement as "the zone
must match the egress IP's country". Re-measuring against the deployment
case shows that is wrong.
The original inference came from reading the host's /etc/timezone
(Asia/Bangkok) and assuming the egress IP was Thai. It is not: this host
egresses from an Indonesian IP. Asia/Bangkok cleared the challenge not
because it matched a country but because it is simply not UTC, and the
two share +07, which hid the distinction.
Measured 2026-08-08, identical container, one Indonesian egress IP:
TZ=UTC never cleared (60s, twice)
TZ=Asia/Jakarta cleared in 4s
TZ=America/New_York cleared in 4s
America/New_York matches neither the country nor the offset nor the
hemisphere, and clears just as fast. So a UTC clock is itself the bot
signal - Cloudflare scores it as the datacenter default - and any real
zone satisfies the check.
This makes the knob considerably less fragile than documented: BROWSER_TZ
needs a plausible zone, not a geolocated one, and a deployment that moves
region does not have to keep it in sync. Comments in chrome/entrypoint.sh
and docker-compose.yml, the hard constraint in AGENTS.md, and the PR
description are corrected accordingly.
BROWSER_TZ is also documented in .env.example for the first time, which
is the file an operator actually copies - the setting decides whether
kagane works at all, and a UTC server (the common case) is exactly the
one that fails with it unset.
Re-verified against the shipped image with TZ=Asia/Jakarta:
TestSmokeKaganeImage PASS (5.00s, 56710 bytes of image/webp),
TestSmokeKaganeGet PASS (1.24s, status 200).
sulthan
1552dd15da