There's a closed pull request on the void-packages repository

[WIP] New package: signal-cli-0.10.5 (java)
https://github.com/void-linux/void-packages/pull/13208

Description:
https://github.com/AsamK/signal-cli

Rudimentary Signal interface written in java for basic cli interactions, based on [libsignal-protocol-java](https://github.com/signalapp/libsignal-protocol-java/)

Unfortunately there doesn't seem to be anything useful based on [libsignal-protocol-c](https://github.com/signalapp/libsignal-protocol-c) yet.
I'm unsure if the package should better be named signal-cli-java instead?

Projects using it include (which i might look into packaging after some evaluation)
- https://github.com/isamert/scli
- https://github.com/TopView/signal-say

___

TODO
- [ ] mention external libraries' licenses
- [ ] fetch external libraries via `distfiles`? (see ghidra for reference)
- [ ] (optional) provide counterparts for the systemd servies (dbus related)