clock
Copyright (c) 2026 cho

The source code in this repository is licensed under the MIT License; see
LICENSE.

This file exists because a built clock is not only this repository's code. It
records what else ends up inside one, and the attribution that comes with it.

--------------------------------------------------------------------------------
ziptz
--------------------------------------------------------------------------------

ZIP code resolution is ziptz, MIT licensed, developed alongside this clock:

    https://github.com/choey/ziptz

A clock carries it rather than merely calling it. `go build` links the Go
package in, so the compiled binary contains ziptz's lookup tables; the Python
install this repository documents copies `ziptz.py` beside `pyclock.py`, which
carries them too. Either way, distributing a clock distributes those tables, and the
attribution below travels with them.

--------------------------------------------------------------------------------
The ZIP tables inside ziptz
--------------------------------------------------------------------------------

Produced from US Census Bureau ZCTA Gazetteer centroids -- a work of the United
States Government, not subject to copyright protection in the United States (17
U.S.C. Sec. 105) -- resolved through timezone-boundary-builder, whose
boundaries derive from OpenStreetMap and are made available under the Open
Database License (ODbL) v1.0.

    https://github.com/evansiroky/timezone-boundary-builder
    https://opendatacommons.org/licenses/odbl/1-0/

Attribution, as ODbL Sec. 4.3 asks for:

    Contains information from timezone-boundary-builder, which is made
    available under the Open Database License (ODbL), and from OpenStreetMap,
    (c) OpenStreetMap contributors.

ziptz's own NOTICE carries this in full, along with the reasoning for treating
1.3 KB of zone names -- no geometry, and nothing the source could be
reconstructed from -- as a produced work rather than an extract of the boundary
database. That file is the authority on the question; this one repeats it so
that a clock distributed on its own is not distributed without it.

--------------------------------------------------------------------------------
The time zone database
--------------------------------------------------------------------------------

Zone names, offsets and abbreviations are read at runtime from whatever tz
database the machine has (the IANA Time Zone Database, public domain). Nothing
from it is copied into this repository. Go falls back to a copy embedded in its
own standard library when the system has none; that copy is covered by the Go
licence, not this one.
