The release is "imminent" as the first pretest is already out. Adding of new features to Emacs 26 has been stopped for a while now. So now only bug fixes and doc improvements happen. 

I have been building Emacs from emacs-26 branch pretty regularly and it's very stable for my daily use. 

Pretest download links:

For GNU/Linux systems: ftp://alpha.gnu.org/gnu/emacs/pretest/emacs-26.0.90.tar.xz

For Windows: http://alpha.gnu.org/gnu/emacs/pretest/windows/

Try it out! :)

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