I believe I have a functioning cygwin environment with all needed code installed.
I've been able to install Attic. The only problem now is that file "xattr.py" has
some extended attribute config/settings for linux, darwin, and freebsd. If that
file doesn't detect one of those OS strings, it fails with exception (see below).

I've looked at the xattr.py code and it is clearly defining and setting up
an environment depending on which OS it detects. Here is my question...
isn't Cygwin essentially (at least) one of these other OS type environments?
I mean, yes...I know it's a Posix implementation on Windows, but doesn't the
implementation itself match (or closely match) one of these existing choices?
That would allow the detection code to be "linux" or "cygwin" for example.

If Cygwin doesn't match, then how hard is it to create this code section for?
And what about simply disabling "extended attribute" support (which I have
seen on other backup programs assuming this is the same type of thing).
The xattr.py code ALREADY has a test as the first function to determine:
"if xattr is enabled on the file system".
So what if we just default to no for cygwin environment. Will that alternately work?

I'm not sure what xattr.py does but my assumption is that it deals with things
like symlinks, owners, and permissions that are not (similarly) present on NTFS,
FAT, and the like. It it handles none of those it is still partially valuable for backup.
And then perhaps a person could create appropriate such code for NTFS scheme
in the future.

$ attic
Traceback (most recent call last):
  File "/usr/bin/attic", line 2, in <module>
    from attic.archiver import main
  File "/usr/lib/python3.2/site-packages/attic/archiver.py", line 13, in <module>
    from attic.archive import Archive, ArchiveChecker
  File "/usr/lib/python3.2/site-packages/attic/archive.py", line 16, in <module>
    from attic import xattr
  File "/usr/lib/python3.2/site-packages/attic/xattr.py", line 251, in <module>
    raise Exception('Unsupported platform: %s' % sys.platform)
Exception: Unsupported platform: cygwin