Q1: Why is there a shopping cart icon on my Firefox tab in my toolbar? Q2: What is this new "Original Profile" business and why can I not edit it?

1. Its your profile avatar. If you wanna change it: Click on the account/profile icon on your toolbar, select Manage Profiles, click your profile, and swap the shopping cart for a different icon or name.

2. The "Original Profile" is your default browser data folder renamed by Firefox during the update. You cannot edit or delete it because it is your active, default profile currently running the open browser window. Firefox locks the active profile to prevent you from accidentally deleting or corrupting your database while the browser is actively reading and writing data to it.

https://support.mozilla.org/en-US/kb/profile-management