Z10b2r0i1e2f0i9n1g3

z10b2r0i1e2f0i9n1g3 (called on the JASRAC database) is Disc 2, Track 3 on the XenobladeX Original Soundtrack. It is split into two parts: the first plays from the start until 2:14, and the second plays from then until the end.

The first part plays when customising Cross, as well as in the following cutscenes:

Main story

 * Nagi and Elma explain FrontierNav to Cross in.
 * The party is briefed on the mission to recover Nelson's team in.
 * The party is briefed on the mission to recover a piece of the Lifehold in.
 * The party is briefed on the mission to investigate the Ma-non Ship being attacked in.
 * The party is briefed on the mission to assist Lao's team during A Friend In Need.
 * The party is briefed on the mission to retrieve the Vita from Noctilum in.
 * Elma sends Gwin off to perform tasks with an underpowered weapon during Boot Camp.
 * and Lin send Cross out to gather materials during A Girl's Wings.

Sidequests

 * Alexa decides to go after Camber and Mika to help them at the start of Rapid Misfire.
 * Bozé introduces himself at the start of The Mad Monk.
 * Bozé accepts the mission to save Clarissa and her team at the start of Bozé's Way.
 * Bozé is briefed on the mission to take out a dangerous indigen at the start of Bozé's Ignorance.
 * The party is briefed on the mission to collect pieces of the White Whale at the start of We Were Soldiers.
 * Frye tells the party about the 'critter cleanup' mission during Bottoms Up.
 * Frye and Phog are briefed on the mission to strike at Bedrock Hold at the start of Blitzkrieg.
 * Phog is updated on the successful breach of Bedrock Hold in the same mission (if the player chooses to protect NLA with Phog).
 * Frye and Phog are briefed on the mission to investigate an odd material in Sylvalum at the start of Brotherly Love.
 * Chausson requests that the party make a peace treaty with the Wrothians at the start of A Challenger Approaches.
 * The party is introduced to H.B. at the start of A New Rival?.
 * The party is briefed on the mission to help out Kiefer and Leland Cole at the start of Fathers and Sons.
 * tells Lin about the weapon R&D work he's been supervising at the start of Two Peas in a Pod.
 * Chausson instructs the party to expand the investigation of the Ganglion at the start of Prospective Partners.
 * Vandham requests that Tatsu make trade deals with the caravans at the start of BFFs.
 * Yelv tells the party he wants to ask around NLA for things to do at the start of Arms and the Man.
 * Yelv tells the party about his partner and the bits of him he's tracked down at the start of Yelv's Partner.

The second part plays in the following cutscenes:

Main story

 * Doug briefs the party on his mission during Close Comrades.
 * The party is briefed on the mission to recover a piece of the Lifehold in.
 * Chausson asks the party to infiltrate Jair Fortress during Spy Games.
 * The party is briefed on the mission to find the supposed piece of the Lifehold in.
 * The party is briefed on the mission to hunt out Ryyz and Dagahn during Manhunt.
 * Vandham apologises for sending the party on a dangerous goose-chase, and asks them to repair a probe in Sylvalum during.
 * Vandham tells the party where the Lifehold Core is and makes Elma acting commander in.

Sidequests

 * Alexa observes the indigens to be used as test subjects for the Ramjet Rifle during Weaponized.
 * Doug tells the party about the unreleased mission to get rid of a pack of indigens at the start of Soldier of the Harriers.
 * The party approaches the Wrothian Stronghold during A Challenger Approaches.
 * H.B. concedes that the party is competent and briefs them on the mission to help Solan during A New Rival?.
 * H.B. and the party learn about Gelvo Banth during The King of Fear.
 * H.B. tells the party about the reason for his suspension at the start of Climbing the Ladder.
 * Lularita requests that the party eliminate the Mold Caro during Hope Springs Eternal.
 * Quentin tells the party of his finding of the database containing Hope's father's journal during A Present for Hope.
 * The party discusses the observed fights between the Wrothians and the Ganglion during Prospective Partners.
 * The party is briefed on the mission to rescue Orton's team at the start of Reporting for Duty.
 * Phog reports to Solan about the bioweapons that attacked them during A Great Divide.
 * Phog learns that Frye needs backup at Bedrock Hold during Blitzkrieg (if the player chooses to protect NLA with Phog).

Etymology
The track title can be split into 3 parts: the prefix 'z10', the digits '20120913', and the letters 'briefing'. The letters likely indicate how this track is used during many cutscenes when the party is briefed on their next mission. The digits can be interpreted as the date 2012/09/13, or the 13th of September 2012, the date in which the track was recorded or mixed.

The track is one of several in the XenobladeX Original Soundtrack beginning with 'z' and a number (possibly followed by 'b'). The significance of this is that the composer Hiroyuki Sawano gives codenames to tracks before he properly titles them: a letter/abbreviation followed by a number, where the letter/abbreviation corresponds to the soundtrack in question. In the case of Xenoblade Chronicles X, this letter was 'z' (Xenoblade X's Japanese name, ゼノブレイドクロス, can be romanised as Zenobureido Kurosu). The number corresponds to the ordering in which tracks were composed. 'z10' is a holdover from this codename.

Therefore, 'z10b2r0i1e2f0i9n1g3' decodes into 'The 10th track composed for Xenoblade X, briefing theme, recorded/mixed on the 13th of September 2012'.