The real action at the Mostly Mozart Festival takes place inside Lincoln Center’s halls, so “Breath,” a multimedia work by Marc Downie and Paul Kaiser of the OpenEnded Group, could be seen as an accompaniment, not the main attraction.But this installation — eight light boxes, corresponding banners and speakers emitting computer-generated music — also has the tall order of functioning as a discrete artwork. It is installed on the exterior of the main-entrance side of Avery Fisher Hall — on the columns and within the ground-floor portico — and is best experienced after sundown (between 8:45 and 11:45, to be specific).Standing with concertgoers examining the 12-foot-tall light boxes in the portico, the word you hear most often is “interesting.” And “Breath” is, in fact, packed full of interesting data and factoids. The first light box takes its inspiration from a story about Mozart buying a pet starling, supposedly after hearing it sing a musical theme he had written. Other light boxes use text and digitally rendered images to explore semantic threads in the 150 Psalms in the Bible, a diagram of the human body breathing, the writings and music of the medieval nun Hildegard of Bingen, the scores of Bach’s and Beethoven’s Masses and the circumstances in which Mozart’s final work, the Requiem, was composed.The spare 56-foot-long banners, illuminated by lights on top of the New York State Theater across the plaza, echo the cream-colored stone of the Avery Fisher building. One includes the words “inhale” and “exhale”; another links the Psalms with Mozart’s starling: “bird,” “soar,” “fly,” “fall,” “rise.” A third describes “Adam’s Fall,” a mystical vision depicted in Hildegard’s 12th-century work “Scivias.” (The neurologist and writer Oliver Sacks has diagnosed her visions as something more prosaic: migraine symptoms.)Speakers along the colonnade play a version of Hildegard’s choral work “Columba aspexit” (“The dove peered in”), with voices recorded in the studio remixed “live” by a computer. What results is a cut-and-paste soundtrack that makes medieval music sound contemporary, although, as musicologists have noted, there are many similarities in the music of the two periods, starting with the simplicity and a penchant for dissonance.Spirituality is one of the main threads in this year’s festival, and “Breath” is an attempt to show how technology can be a vehicle for it. But where digital images, from art to medical imaging, can inspire profundity, those in “Breath,” which most resemble advertising graphics, business presentations and scientific diagrams, don’t inspire much wonder. The installation might be interesting to see and hear during intermission or after a concert, but it is not really worth a pilgrimage.