This has been tested with Windows Python 2.7 and Python 3.8

If you get the ZipInfo objects of a ZIP file that is larger than 2GiB, then all the ZipInfo entries with a header offset > 2G will report phantom 'extra' data.

import zipfile
zipname = "reallybig.zip"
z = zipfile.ZipFile( zipname )
zi = z.infolist()
for inf in zi:
      print( inf.filename, inf.header_offset, inf.extra )  

And observe that:
* All entries with offset < 2G will report no extra field.
* All entries with offset > 2G will report extra field.

It's hard to package this up as a self-contained test, because it requires a very large zip to test.