How does Dynatrace make use of persistent cookie for user tracking?

[WeilinT]

Understand from https://www.dynatrace.com/support/help/shortlink/user-session#user-session-identification, that user identification is achieved by storing a persistent cookie within each user's browser. - Is it correct to assume that cookies are always set whether or not "Use persistent cookies for user tracking" is enable? Cause for my trial, i never enable the function but is still able to detect new vs returning user hence i assumed that cookies are always set. 

What enabling "Use persistent cookies for user tracking" does is, it will backup the cookies in localStorage instead of sessionStorage. I get that the idea is to make sure cookies are not deleted. Hence by enabling this function does it mean that if Dynatrace detected missing cookies, it will first look for localStorage or sessionStorage to check if there is backup cookies? if there is no cookies, it will set new cookies for the browser?

Also are these cookies unique per browser or per domain? if i have different applications (with different domains) does Dynatrace set a different cookies for each application or does it use the same one such that if i were to click into the user tag i am able to see that the user visited the different applications?

Lastly, what is the lifespan of the cookie now, is it lifetime? noted that there are configuration to shorten the lifetime, hence by default does it exist forever until someone/browser deletes it?

Thanks so much for the help in advance.  

[WeilinT]

@abdullahhhh0101 really appreciate for the explanation on persistent cookies.

However i am more keen to find out how does Dynatrace make sure of the persistent cookies, hence some of my questions are still not answer so i will have to mark your answer as not the solution.

Understand that Dynatrace set these cookies:

• rxVisitor
• rxvisitid
• rxvt
• dtsrNOSR 1

Hence would like to find out:

1. Does Dynatrace set these persistent cookies with/without enabling "Use persistent cookies for user tracking"

2. How does Dynatrace make use of the backup in localStorage or sessionStorage to identify user? Do they read the backup and set the cookies in the event cookies are deleted?

3.  Are these cookies unique per browser or per domain? if i have different applications (with different domains) does Dynatrace set a different cookies for each application or does it use the same one such that if i were to click into the user tag i am able to see that the user visited the different applications?

4. When Dynatrace set these cookies, is there a default lifetime that they configure to? like 12 months? or its forever until its deleted by someone or browser?

Thanks.