mobile

I'm seeing a lot of posts about folks flashing "ultimate kernel". It sounds like something I want. Just not 100% on what it is. I've tried Googleing it and from what I can tell it's only for the exyos processor. I have a USA t-mobile note 4 with the qualcomm.

What is it.
Can I get it.
Do I want it.

Thanks for any info. Sorry if this is a dumb question or its been asked before.