Minecraft wiki entry for Development_versions, associated text: The launcher can now be used to play the Java Edition demo without a login.
Improved accessibility and screen reader usability.
Launcher window sizing and positioning has been overhauled on all platforms.
Launcher logging improvements: launcher components append to, instead of overwriting, the log.
Launcher can now resume interrupted downloads where applicable.
Display scaling support has been improved on Windows.
Launcher now has better desktop integration on Linux, and can use system dialogs (file browsing and similar).
Linux packages no longer depend on Java 8, instead they require any suitable Java runtime environment.
A dependency on GTK 3 has also been added.
Improved UI performance.