What are these Extended Attributes (EAs) in the files in Windows 8?

When I run CheckDisk on a Windows 8 Consumer Preview volume, I get:

> chkdsk /v S:The type of the file system is NTFS.Volume label is Windows 8.WARNING!  F parameter not specified.Running CHKDSK in read-only mode.CHKDSK is verifying files (stage 1 of 3)...  91392 file records processed.File verification completed.  28 large file records processed.  0 bad file records processed.  20224 EA records processed.                 <------------------ huh??

Why are there so many extended attributes on the volume? I thought no one used EAs anymore...

Edit:

As an example, the file \Windows\CSC\v2.0.6 has an extended attribute that contains the string

Ԡ 1X C8A05BC0-3FA8-49E9-8148-61EE14A67687.CSC.DATABASE P X Չ: Չ: ˌΦ]cᑡPcďŠ 4 C8A05BC0-3FA8-49E9-8148-61EE14A67687.CSC.DATABASEEX1 P X _, N0t 08 C8A05BC0-3FA8-49E9-8148-61EE14A67687.CSC.EPOCHEA 8 ͌Φ]cᑡPcďŠ }

which (thanks to an answer below) seems to be related to client-side caching of offline files.

However, it seems like most other EAs are different -- e.g. the file

\Program Files\WindowsApps      \Microsoft.BingFinance_1.0.1022.0_x64__8wekyb3d8bbwe\pages\ETF\js\ETF.js

and most other files contains (mostly) the string $KERNEL.PURGE.APPXFICACHE, which doesn't seem to be related. What might this be for?