I just see from the Ussylis channel and I notice this HUD, so strange. Does anyone know what is this mean?
Youtube link(start at 6:58)
He does have a custom skin on it, that's supposed to be a exhaustion I think.
That's correct, it seems to be the exhaustion status effect from the looks of what the icon is supposed to represent.
Some players can modify certain things in-game like Killer/Survivor portraits or perk colors/skins, this is only client sided and does nothing to gain and advantage in-game.
What's happening here is that this seems to be a custom skin for one of the status effects (presumably Exhaustion from what the icon is showing), so that's why this status effect isn't shown anywhere else, because it's not an official status effect, it's just a skin that's replacing a pre-existing icon for another status effect.
You might ask "How can I do this?", for that I personally don't know, but whenever someone does this type of modifications in-game, it's usually something that's "at your own risk" per-say. BHVR has stated that exact thing when players mention stuff like this, but they don't support doing it either.
The reason it's labeled under "do at your own risk" is because BHVR might not ban you for it, but the cheat engine software DBD runs on, EAC (Easy Anti-Cheat) might detect it as a hack and give you a EAC ban as a result.
Thanks for all the answer.
No problem, glad we could help.