The official Raspberry Pi OS (formerly Raspbian) has been updated and it’s now based on the Debian GNU/Linux 11 “Bullseye” operating system series.
The latest Raspberry Pi OS release, dated October 30th, 2021, is the first to switch bases from the old-stable Debian GNU/Linux 10 “Buster” to the Debian GNU/Linux 11 “Bullseye” operating system series, and it uses the Linux 5.10.63 LTS kernel by default.
But the Debian Bullseye rebase is just the cherry on top, as the newest Raspberry Pi OS release features all of its desktop components and applications build against the GTK+ 3 open-source application framework for the in-house built PIXEL desktop environment based on LXDE.
These include the LXPanel and all of its plugins, the PCManFM file manager and libfm library, as well as the piwiz first-run startup wizard, pipanel preferences application, rc_gui raspi-config GUI, and LXinput keyboard and mouse settings app.