Z13e20v12e09n14t

z13e20v12e09n14t (called on the JASRAC database) is Disc 2, Track 14 on the XenobladeX Original Soundtrack. It is split into two parts: the first plays from the start until 2:48, and the second plays from then until the end.

The first part plays in the following cutscenes:

Main story

 * Lin finds the origin of the Pathfinders' IFF signal in.
 * Lao is introduced to Elma's (new) team in.
 * Elma,, Nagi, and Chausson conclude that the Ganglion were the ones who attacked Earth at the end of Chapter 4.
 * The party investigates the Vita in Noctilum in.
 * The party considers the Vita after bringing it back to NLA in Chapter 6.
 * The party and two Marnuck Soldiers find Celica and Rock's fire pit during Manhunt.
 * Gwin and Mathias lie in wait after preparing a trap to bring Aisha home during Nine Lives.

Sidequests
A variation of the first part with substantially louder pads at the start of the piece plays in the following cutscenes:
 * Ackwar introduces himself at the start of Murder Most Foul.
 * Powell reveals that he poisoned people with pizza during the same mission.
 * The party encounters Malyteth at Biahno Lake for the first time during The Miracle Maker.
 * DE913: Dieara claims HT665: Erio is not sufficiently loyal to the Ganglion during Attack on Biahno Hills.
 * The party threatens Fortun for the access code at the start of Definian Downfall.
 * Alexa deduces that Mika was attacked by Ganglion Skells during Rapid Misfire.
 * Hope learns that her clients have been disappearing at the start of A False Hope.
 * Brenna brushes off Lin's idea to increase the beam cannon's output during Two Peas in a Pod.
 * Murderess 'randomly' ends up with Yolanda's hardest challenge during The Little Rich Girl.
 * Eleonora briefs Murderess on the mission to capture the Orphe scientist in the same mission.
 * Murderess requests Eleonora for intel regarding a string of murders during Serial Thriller.
 * Murderess accuses Dart of being Dale Gibbon in the same mission.
 * Elma introduces Lin's request to ask around NLA for traditional xeno recipes during To Serve Nopon.
 * The party meets De Sazon during Leaving the Nest.
 * The Blood Lobster notifies Cross about the lobster bombs at the start of Rise of the Blood Lobster.
 * Gi Zang and Tolba Wolfen 'reunite' during The Duel (Part IV).
 * The party 'confronts' Leroy in his Skell during Forbidden Love (if the player doubted that Leroy could take care of Lavina Couba).

The second plays in the following cutscenes:
 * Elma receives word that BLADEs are under attack near her location during Renewed Will.
 * The party and Luxaar independently reflect upon the Ganglion recovering the Vita in.
 * Bozé investigates the damaged Skells of Clarissa and her team during Bozé's Way.
 * Murderess and Irina butt heads when Cross first meets the former at the start of My Dream.
 * Murderess and Dale Gibbon verbally spar in Sylvalum before fighting during Serial Thriller.
 * requests that the party quickly find Nagi at the start of Nagi's Time.
 * Phog considers the Oc-Serv Yabar which attacked the party during A Great Divide.
 * Tatsu misinterprets Lin's excited reaction to hearing about a new recipe during To Serve Nopon.

Etymology
The track title can be split into 3 parts: the prefix 'z13', the digits '20120914', and the letters 'event'. The digits can be interpreted as the date 2012/09/14, or the 14th 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. 'z13' is a holdover from this codename.

Therefore, 'z13e20v12e09n14t' decodes into 'The 13th track composed for Xenoblade X, event theme, recorded/mixed on the 14th of September 2012'.