A fully black dark teal bar with some transparency, indicates "level of concern". Levels should indicate, how aware the Warden is of the player. Algorithm TBD, but could be started/ended by the presence of the darkness effect and level could be evaluated by some warden/shrieker client-side sounds.

The text should be -snumber (s like sound) or -🔔number

https://minecraft.fandom.com/wiki/Warden
https://minecraft.fandom.com/wiki/Sculk_Shrieker
https://minecraft.fandom.com/wiki/Java_Edition_1.19#Mobs

Currently implemented by just stabilizing the darkness effect duration (aka you will see when it actually fades instead of the fluctuation), because I don't really know how to track for the client-side sounds. Hopefully someone makes a mod for this from which I can learn/copy from...

Edit: https://github.com/IntelligentCreations/Hudium/tree/feature/warden-info for reference

As of 3.1.0, OneBar shows Warden's raw general anger level instead. Also tried to add the despawn time to the calculation, but it was very hard to properly calculate from clientside.

Edit: also tried getting the anger level that is directed towards the player, but it was very inconsistent - e.g. the player would aggrevate at first but when they make vibrations, that increased anger is not set directly towards the same player, despite the warden hunting that player.