A fair number of changes have been made to the text of the Z-Machine Standards Document (versions 1.0 and 1.1), and while these updated files are available on Github, that’s not very useful if you’re interested in actually viewing the latest version of the Z-Machine Standard.
In light of this, I have made them available (possibly temporarily, if they find a better home) at http://frobnitz.co.uk/zmachine/