Custom bolt messaging
The custom bolt messaging service alters the attack messaging on a bolt spell by customizing both the verb (e.g. hurl, toss, throw, fling, breathe, exhale, direct) and the object that is thrown. The service may be offered via pre-made options or via full customization, which causes it to be a delayed service.
Cone of Elements (518) casts the applicable individual bolt spells at each target, so if a wizard customizes Minor Fire (906), then casts Cone of Elements with Minor Fire, it will use the custom Minor Fire messaging. Major Air Bolt doesn't exist as an individual spell, but it can still be customized for when it is cast via Cone of Elements.
The big bolded phrase is the customization, replacing the standard spell message: "hurl a roaring ball of fire."
>incant 908 Your hands glow with power as you invoke the phrase for Major Fire... Your spell is ready. You gesture at a giant rat. You conjure a sizzling red hot fireball at a giant rat! AS: +12 vs DS: -27 with AvD: +70 + d100 roll: +78 = +187 ... and hit for 60 points of damage! Extreme heat causes a giant rat's right leg to expand and snap. That must hurt! The giant rat is stunned! The roaring ball of fire strikes a giant rat, blossoming into a much larger sphere of flame upon impact. ... 45 points of damage! Left leg completely charred. Cast Roundtime 3 Seconds