build.py makes the app's catalogue of deep-sky objects, shared/ui/src/commonMain/composeResources/files/catalogue.tsv, from OpenNGC by Mattia Verga, with the common names of names.tsv.

OpenNGC is distributed under CC BY-SA 4.0. The catalogue made from it, and names.tsv, are distributed under that same licence, not under the MPL-2.0 of the rest of Yacana. The app credits OpenNGC in Settings › About and in Settings › About › Open-source licences.