Proceed through the mission until you leave the air vents, and a cutscene will begin. Hold Select to skip the cutscene. Stealth kill four enemies, and then disposed of the final enemy as desired. After defeating the last enemy, pause the game.
ZZ-CT is a 3x3 method proposed by Chris Tran. It is a variant of the ZZ Method with a unique 2 look LSLL, divided into TSLE and TTLL. TSLE inserts the last edge whilst orienting all corners.
xz is a lossless data compression program and file format which incorporates the LZMA/LZMA2 compression algorithms. One can think of xz as a stripped-down version of the 7-Zip program. xz has its own file format rather than the .7z format used by 7-Zip (which lacks support for Unix-like file system metadata).