From the release announcement:
* Port to ARM AArch64 contributed by Linaro.
From that organization's website:
"it wants to provide the best software foundations to everyone, and to reduce non-differentiating and costly low level fragmentation."
"Linaro was established in June 2010 by founding members ARM, Freescale, IBM, Samsung, ST-Ericsson and Texas instruments (TI). Members provide engineering resources and funding. Linaro's goals are to deliver value to its members through enabling their engineering teams to focus on differentiation and product delivery, and to reduce time to market for OEM/ODMs delivering open source based products using ARM technology."
(member list quite a bit longer than above names)
In other words: many commercial enterprises, that are in it for the money and fighting each other in the marketplace, but working together to improve something that's out there in the open, free for all to use. So that what's common to all, is the best it can be, and each vendor can focus its resources on what makes their product different from the rest of the pack.
Sigh - how much better life could be if that principle were applied more often...