Email link branding (formerly "Link Whitelabel") allows all of the click-tracked links, opens, and images in your emails to be served from your domain rather than sendgrid.net. Spam filters and recipient servers look at the links within emails to determine whether the email looks trustworthy. They use the reputation of the root domain to determine whether the links can be trusted.
You can also manage link branding in the Sender Authentication section of the Twilio SendGrid App.
For more information, please see our Link Branding documentation.