; <code>utm_content</code>: '''The distribution name'''. Must be unique. Identifies the distribution name.
; <code>utm_campaign</code>: '''The campaign name'''. Must be <code>distribution</code>.
; <code>utm_source</code>: Original referrer. E.g., <code>mozilla</code>. Not used by Firefoxfor downloadable distributions, but is used for campaign tracking.
; <code>utm_medium</code>: Campaign medium. E.g., <code>email</code>. Not used by Firefox.
; <code>utm_term</code>: Search terms. E.g., <code>web+browser</code>. Not used by Firefox.