Mozilla announced  Firefox Reality today, "Bringing the Immersive Web to Mixed Reality Headsets". Firefox Reality is the only open source browser for mixed reality and the first cross-platform browser for mixed reality. See The Mozilla Blog for more details.
GnuCash 3.0 was released yesterday, marking the first stable release in the 3.x series. This version has several new features, but the main update is the use of the Gtk+-3.0 Toolkit and the WebKit2Gtk API. See the announcement for a list of all the new features for both users and developers.
Kernel 4.17 will have 500,000 fewer lines of code, as maintainers have decided to deprecate support for old CPU architectures. As written in the pull request on the LKML, "This removes the entire architecture code for blackfin, cris, frv, m32r, metag, mn10300, score, and tile, including the associated device drivers."
Compete in the second annual Linux Game Jam! Submissions will be accepted starting April 5th and the deadline is April 14th. This year's theme is "Versatile Verbs". See the website for all the rules.
And in other new releases, the OpenBSD team announced new version 6.3 yesterday. This update features SMP support on arm64 and multiple security improvements, including Meltdown/Spectre (variant 2) mitigations. See the release page for the complete list of changes.