Interestingly, Raspbian Buster is debuting slightly ahead of the official Debian release. The Raspberry Pi Foundation says this is because the open source OpenGL video driver is now being used by default, and it was developed using the most recent version of Debian.
"It would have been a lot of work to port everything required for it back on to Raspbian Stretch, so we decided that we would launch on Raspbian Buster—the only question was whether Buster would be ready before the hardware was!," the Raspberry Pi Foundation stated in a blog post.
"There are no huge differences between Debian Stretch and Debian Buster. In a sad reflection of the way the world is nowadays, most of the differences are security changes designed to make Buster harder to hack. Any other differences are mostly small incremental changes that most people won’t notice," the Raspberry Pi Foundation said.
Raspberry Pi 4 1GB Model (Source: CanaKit)
One thing the developers focused on with Buster is making it visually different from previous versions. The overall appearance of the desktop has remained largely the same for a few years now, and is a bit dated. So, Buster gets a "mild refresh" (think of it as a shot of Botox, as opposed to an all-out facelift).
In addition, Buster makes the Thonny Python development environment its default Python editor (IDLE is no longer included by default). For those who want an alternative, the Mu Python IDE is also still available in Recommended Software.
Other changes include tweaks to the taskbar, a new Screen Configuration tool when the GL driver is in use, hardware acceleration for the desktop environment (when using the new Raspberry Pi 4), a USB Attached SCSI Protocol (UASP) driver in place of the USB Mass Storage (UMS) driver, and a few other bits.