Regarding the link to receive reviews

Hi guys
I’m working with an agency to integrate Klaviyo with this plugin.
We need to understand how the ‘request review’ link works. Here is the link I’m referring to:
https://www.sample.com/review/?product_id=8862&user_name=RGFuaWVs&user_email=ZGFuaWVsa2FybmlAZ21haWwuY29t

We understand ‘product_id’.
But user_name & user_email are hashed.

We aim to generate our own links to embed them in Klaviyo emails.
I have renewed my support to get help from you, and I am looking forward to hearing from you

Daniel