suncalc.js - SunCalc (v1.9.0)
Source: https://github.com/mourner/suncalc
Original author: Vladimir Agafonkin (mourner)
License: ISC (https://github.com/mourner/suncalc/blob/master/LICENSE)
Used under the terms of the ISC License.

stars.json - star catalogue derived from the Yale Bright Star Catalogue
(5th ed., public catalogue data). Generated for this project; see the
real-sky notes in clouds3d.js.

moon.jpg - equirectangular near-side lunar map (1024x512, downscaled from
the 2048x1024 original) used for the moon disc texture.
Source: https://www.solarsystemscope.com/textures/ (via Wikimedia Commons,
"Solarsystemscope texture 2k moon.jpg")
Author: Solar System Scope
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
Attribution required: Solar System Scope / solarsystemscope.com

plane3d.js - low-poly airliner mesh (480 triangles, flat shaded, no textures)
Original geometry generated by tools/plane_gen.py in this repository; offered
under CC0 1.0 like the rest of the project's own assets.

clouds3d.js - original code for this project (same license as the
repository root LICENSE).

These libraries/data files are vendored locally so the application can
run fully offline without any external network dependencies.