It’s not a regular program that you click on, it’s an input add-on. I installed it but it it doesn’t seem to do anything, even after a reboot.
But hey, it’s 25 years old, according to the README.
HanBe for Haiku - Korean Input Server Method
Version 1.0
Copyright 1998-2020, Sangwon Lee (itools@gmail.com)
All rights reserved. Distributed under the terms of the MIT license.
Your best bet is to ask Sangwon Lee if the source code is still floating around and put it up on HaikuArchives for people to look at it. Or see if you can live with BeCJK instead.
Why does that matter? Haiku is younger than that. Code doesn’t suddenly become broken when some time has elapsed, if it worked in beta4 but doesn’t in beta5 we should probably check out why