It's included in the latest babble-boss. I've tried adding "Halion" to the defaultAddedBosses-Section and his Death-Yell as well to the bossDefeatedYells-Section. It is working for Sindragosa, Valithria and other Bosses.
Wow patch 4.01:
After killing a boss and awarding loot, the loot note dialog pops up, any value entered there won't be accepted, the loot note dialog only can be closed with clicking on the cancel button.