[Edited 2022: please note, this no longer works.
But you can upload a list of emails to LinkedIn and find out who these people are. >> How to Verify Email Guesses on the Professional Network]
Here is a way to uncover all that that extension does – even without the need for Chrome or Gmail. This link works in any browser – Chrome, Firefox, Opera, or any other.
Replace the email address at the end with an email that you would like to use – and find the person’s LinkedIn profile. (This link can also verify that the email address exists.) The link works reliably, and it’s fast! You do not need a Sales Navigator subscription; you need to be logged into LinkedIn.
Here is what you would see when using the link above: