It is an email with an explanation of what you do, then some screenshots with code. People who mostly delivered value by writing code at Google wrote an explanation what they did, and often linked to different changelists with code they had written. The only strange part here is the screenshots of code instead of PR's, but adapting to that isn't very hard, take some screen shot of the diff or some part of the code and explain how that code fullfills the things you talked about in the email.

A person who can't do that lacks the soft skills to be an effective software engineer.