Redis - How kombu actually deals with the visibility_timeout

[V0lantis]

Hello,

I am using celery as a queue broker with redis as a PubSub interface. I have an issue with workers shutting down, and I was trying to mitigate this issue.
While reading the code, I understood that celery was using Kombu under the hood to communicate with Redis. Unfortunately, I haven't been able to understand the code properly, and how Celery + kombu actually implements the visibility_timeout process.
I am not very accustomed on how redis works, so it is even harder to debug what's happening. Though, I have been able to see that Kombu or celery was creating 3 keys when we launch the program :

1) "_kombu.binding.celery"
2) "_kombu.binding.celeryev"
3) "_kombu.binding.celery.pidbox"

Are those keys have anything to do with visibility_timeout?
Since, visibility_timeout is not natively implemented in redis, how do you create this behavior?

Thank-you for any help you could give me, or any hint to a blog article explaining this