Update: Mozilla failed to include in the Release Notes that the the update includes critical security fixes.
Updates for Firefox Version 63.0 include fourteen (14) security updates in which 2 are rated Critical, 3 High, 4 Moderate and 5 Low.
Updates for Firefox ESR Version 60.3 include eight (8) security updates in which 1 is rated Critical, 3 High, 3 Moderate and 1 Low.