appears to be a specific file naming convention or a search string typically used on file-sharing or unofficial streaming platforms. It refers to the 2017 theatrical version Justice League 4K Ultra High Definition (2160p) Technical Breakdown of the Title

Most high-quality files of ZSJL hover around 60 to 90 gigabytes. "Extra quality" files (Remuxes) hit 100GB+. Why? Because a 4-hour movie requires significant data to maintain visual fidelity. If you watch a 5GB compressed version, the final battle on the Apokoliptian terrain looks like a video game from 2010. At 2160p with "extra quality," you see the micro-expressions on Ray Fisher’s Cyborg face—CGI that was painstakingly rendered at 4K resolution.