The architectural reconfiguration system was a TARDIS component in the shape of a tree that the Eleventh Doctor described as "a machine that makes machines" by "reconstructing the particles according to your needs." It was, according to Gregor Van Baalen's scanner, "more valuable than the total sum of any currency."
In an alternate timeline that was later erased, Gregor discovered the architectural reconfiguration system and, against the Doctor's warnings, disconnected one of the system's orbs out of pure greed. The TARDIS defended herself by locking him, Tricky and the Doctor in a space loop, as well as sealing the TARDIS doors. (TV: Journey to the Centre of the TARDIS)
During the Last Great Time War, Heleyna sabotaged Vassarian's Battle TARDIS reconfiguration system to stop the War Doctor from following her and stop her destruction of the Eye of Harmony. The Doctor used this idea and destroyed the Battle TARDIS' star chamber to stop the Dalek Time Strategist's plan. (AUDIO: Eye of Harmony)
When the Twelfth Doctor trekked through a damaged TARDIS, he found it infested by Spyrillites, following them to the architectural reconfiguration system, the sight of it allowed him to realise that he was in TARDIS. (COMIC: Playing House)
A Time Lord author noted a rumour that the Celestial Intervention Agency's headquarters in the Capitol was constantly relocated via architectural reconfiguration. (PROSE: A Brief History of Time Lords)