The ShackTac User Interface (STUI) compilation includes a number of different ShackTac mods, which you can read about here:
https://gitlab.com/shacktac-public/general/wikis/home

Found an issue? You can report that on a GitLab tracker here:
https://gitlab.com/shacktac-public/general/issues

Usage of STUI requires agreement with the following terms. STUI may NOT be modified, included in other mods in whole or part, used for military training or any commercial purposes whatsoever, without prior permission from the authors (generally zx64 and dslyecxi). Redistribution of the addon via community repos etc is permitted only if it is unmodified and free of charge. You may choose to only include specific addons in your repo, but may not modify the actual PBOs themselves. Modifications are forbidden without prior permission from the authors.

You can reach the authors at dslyecxi@gmail.com