Mosaic brings automatic tiling to GNOME Shell, but without asking you to use it permanently. Pop!_OS has since moved from GNOME Shell to the COSMIC desktop, with similar functionality built into the desktop. Mosaic’s developer says the extension aims for “simple and intuitive window management as well as minimal configuration and sane defaults” and was inspired by the Rethinking Window Management blog post from GNOME’s Tobias Bernard . It certainly meets a different use case to, say, Tiling Shell, the adaptive window tiling extension for GNOME Shell I’ve written about before. Mosaic is less fussy with less complexity than that (and some other window tiling extensions for GNOME Shell).