That was also my thought. To my knowledge `/etc/localtime` is the creation of Arthur David Olson, the founder of the tz database (now maintained by IANA), but h

That was also my thought. To my knowledge `/etc/localtime` is the creation of Arthur David Olson, the founder of the tz database (now maintained by IANA), but his code never read `/etc/localtime` multiple times unless `TZ` environment variable was changed. Tzcode made into glibc but Ulrich Drepper changed it to not cache `/etc/localtime` when `TZ` is unset [1]; I wasn't able to locate the exact rationale, given that the commit was very ancient (1996-12) and no mailing list archive is available for this time period. [1] https://github.com/bminor/glibc/commit/68dbb3a69e78e24a778c6602c8cc91d715839d08#diff-680a4b70a0fc1a41c25225534c76b25bd0861a198141b0f2635f13a2b6fa9de8 https://github.com/bminor/glibc/commit/68dbb3a69e78e24a778c6...