# Licensing and attribution

QCALVIEW source code is released under the **GNU General Public License v3.0 or later (GPL-3.0-or-later)**.

Copyright © 2026 **Fabrice Kerzerho — ArcTan°**.

The GPL permits use, study, modification and redistribution under its terms, including preservation of applicable copyright and licence notices and identification of modified versions where required.

The names **QCALVIEW**, **ArcTan°**, associated logos and visual identity are branding assets and are not granted for unrestricted branding use merely because the source code is GPL-licensed. See `TRADEMARKS.md`.

Redistributions and modified versions should preserve the applicable copyright/licence attribution described in the root `NOTICE` file. Using QCALVIEW to produce a map, image or report does not by itself require adding a QCALVIEW/ArcTan° credit to that output.
