Question About wp_woocommerce_sessions Entries

I understand that sessions are stored in wp_woocommerce_sessions but I have a few questions about that table. I’m trying to understand how long sessions stay in the table as well as how to use some of the data.

Looking through Google I found information about sessions before the wp_woocommerce_sessions table was introduced. Some of the stuff I found had information about WooCommerce using built in cron jobs to remove sessions.

My first question is:

Besides the button in the admin menu to clear customer sessions is there any sort of automated removal of records from wp_woocommerce_sessions built into WooCommerce? Do sessions now stay in that table forever unless cleared out manually by the admin menu button?

My second question is:

One of the columns in wp_woocommerce_sessions is named session_expiry and is storing numbers such as 1470105964. What is that number relative too?