In 3.6.1, the manual, section 3.1.3, has this to say:

"Your administrator will need to activate the “Enable Win32 long paths” group policy, or set the registry value HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem@LongPathsEnabled to 1."

Separating a value name from the key path with an @-sign, which is what the above is doing, is something I have never before seen anywhere. I suggest changing it by either:

- replacing the instructions for the manual change with a link to <https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath> or a more suitable reference (I could not find a KB article when I looked)

- rewording it as, e.g.,

  ... in the registry key HKEY_...FileSystem, set the REG_DWORD value LongPathsEnabled to 1

  The value type could be left out; the value is predefined on all platforms where it will be effective.

Pull requests welcome, but as someone who lives in the Windows API day in and day out, I can vouch for it being the normal abbreviated way of specifying a fully qualified registry value.

Out of curiosity, can you point me to an example or two?

I have been living with, though not in, Win32 for quite a few years myself, and I can say with certainty that I have never seen this notation before in my life.

Other than that, PR on the way soonish.

There's a handful of references in https://docs.microsoft.com/en-us/visualstudio/ide/walkthrough-creating-a-multiple-computer-build-environment, though TBH most of the docs written by actual doc writers use more complicated sentences to avoid it.

It's also the syntax used by MSBuild, which is probably mostly why I think it's normal.

@chrullrich, were you still interested in creating a PR for this?  Thanks!

New changeset ff1ae3dd334faa2006394c2318db385cdc42030a by Zackery Spytz in branch 'master':
bpo-30612: Tweak Windows registry path syntax in the docs (GH-20281)
https://github.com/python/cpython/commit/ff1ae3dd334faa2006394c2318db385cdc42030a

New changeset f53ea8adaecacfe8c1e4a093136fb5318b15d779 by Miss Skeleton (bot) in branch '3.8':
bpo-30612: Tweak Windows registry path syntax in the docs (GH-20281)
https://github.com/python/cpython/commit/f53ea8adaecacfe8c1e4a093136fb5318b15d779

New changeset bd9d76bbbb9eb226d99e186dae39e06ba8977485 by Miss Skeleton (bot) in branch '3.9':
bpo-30612: Tweak Windows registry path syntax in the docs (GH-20281)
https://github.com/python/cpython/commit/bd9d76bbbb9eb226d99e186dae39e06ba8977485