# Notice

Psysonic is licensed under the GNU GPLv3.

Psysonic, including features such as **Orbit** (synchronized shared
listening sessions), was originally designed and implemented by the
Psysonic project maintainers and contributors.

Forks and modified versions are welcome under the GPLv3, but they
must preserve copyright notices, license information, and clear
attribution to the original Psysonic project.

Modified versions must not imply that original Psysonic features were
independently created by the fork, nor imply endorsement by the
Psysonic project.

## Required Attribution for Derivative Works

The following attribution requirements apply to all derivative works
under the additional terms permitted by **GPLv3 §7(b)**. Forks and
redistributions must preserve these notices intact:

1. The unmodified contents of this `NOTICE.md` file must be retained
   in the source tree of any fork or derivative work.
2. Derivative works that include or are based on the **Orbit**
   feature — its design, protocol, or implementation — must clearly
   state in their own documentation and release notes that the Orbit
   feature was originally designed and implemented in Psysonic, and
   must not present Orbit's design or implementation as independent
   original work of the fork.
3. The user-facing name "Orbit" is a Psysonic feature mark and may
   not be reused by forks; see `TRADEMARK.md`. The attribution
   requirement in (2) applies regardless of what the feature is
   renamed to in a fork.
4. The same applies to any other original Psysonic feature that a
   fork chooses to retain.

These terms do not restrict the freedoms granted by the GPLv3; they
are attribution-preservation terms explicitly permitted by GPLv3
§7(b) and must be carried forward in further redistribution.
