Can something that's just taken a couple of months to arrive still be considered "long-awaited"? If so, the official Linux UEFI pre-bootloader fits the bill, as it's something that's been needed ever since the introduction of the Microsoft-pushed Secure Boot mechanism on UEFI-equipped PCs. We've talked about this pre-bootloader a couple of times in the past. Its goal is simple: to allow Linux OSes to boot up on systems that have Secure Boot enabled. The work-around hasn't been so simple, but it's happened.
As discussed last week, this pre-bootloader was recently re-written in order to support every bootloader that could exist, including GRUB and Gummiboot - the latter of which respects Secure Boot's authentication handshake. With this official release, distro developers are able to adopt it and deploy it as soon as they deem fit. Because this is a very low-level addition that could run the risk of introducing problems, it's not likely that we'll see it in mainstream distros right away.
Developers can download a pre-built mini-USB image that employs the pre-bootloader so that it can be seen in action, and simple instructions are given to those who are interested in testing it out with their own distros.
The developers of this pre-bootloader deserve a big kudos, especially James Bottomley who has kept us up-to-date through the entire process. From start to finish, the development process didn't take too long at all, but I'm sure there was still a ton of work involved. But now it's here, and we can start worrying about the next step Microsoft takes to try to thwart Linux's growth!