The following bug has been logged online:
Bug reference: 6151
Logged by: Christoph Anton Mitterer
Email address: email@example.com
PostgreSQL version: 9.0
Operating system: Debian sid
Description: documentation claims that default value for log_timezone
The documentation tells
OG-TIMEZONE) that the default for log_timezone is "unknown".
It seems however that this is rather "localtime".
(This possibly also appears in the default postgres.conf)