Short answers, pulled from the story.
StageCraft is an on-set virtual production visual effects technology built around a high-definition LED video wall. It was designed by Industrial Light & Magic (ILM) for the Disney+ series The Mandalorian. The soundstage where it is implemented is called The Volume.
Cinematographer Greig Fraser encountered multiple issues while shooting Rogue One in 2016, which gave rise to the idea of using large LED screens as part of the set. The concept was developed further by a team that included ILM's Richard Bluff and Rob Bredow, as well as Kim Libreri of Epic Games.
StageCraft surrounds live-action actors with large, very high-definition LED video walls displaying computer-generated imagery in real time. The background can be realigned instantly as the camera moves, replacing the traditional approach of compositing backgrounds in post-production using chroma key screens. ILM uses Epic Games' Unreal Engine to handle the real-time three-dimensional rendering.
StageCraft 2.0 was an upgraded version of the technology introduced for the second season of The Mandalorian. It featured a larger volume and more specialized software, including Helios, a rendering engine designed by ILM specifically for StageCraft hardware.
Permanent volumes were announced at Manhattan Beach Studios in Los Angeles, Pinewood Studios in London, Fox Studios Australia, and Vancouver. The London volume was planned to open in February 2021, the second Los Angeles volume was expected to complete in March 2021, and the Vancouver volume was announced in November 2021 with an early 2022 opening planned.
Television series using StageCraft include The Mandalorian, The Book of Boba Fett, Obi-Wan Kenobi, Andor, House of the Dragon, Ahsoka, Percy Jackson and the Olympians, Doctor Who series 14, and Avatar: The Last Airbender, among others. Feature films include The Batman, Thor: Love and Thunder, Black Adam, The Fabelmans, Ant-Man and the Wasp: Quantumania, The Creator, and Tron: Ares.