Bug#1053672: Apple copyright notices in test .xlsx files

[Rebecca N. Palmer]

Source: openpyxl
Version: 3.0.9-2
Severity: serious

licensecheck -r --copyright . on openpyxl finds these:

./openpyxl/formatting/tests/data/conditional-formatting.xlsx: UNKNOWN
[Copyright: 2007 Apple Inc.]
./openpyxl/reader/tests/data/complex-styles.xlsx: UNKNOWN
[Copyright: 2007 Apple Inc.]

If opened in 'less' these files do contain the text "Copyright 2007
Apple Inc., all rights reserved.", marked as 'etext'.

However, if opened in LibreOffice, no _obvious_ command displays this
text. File > Properties instead displays creation and modification
dates/authors that match the openpyxl upstream commit dates/authors
(2012-4), which suggests that these are *not* straightforward copies of
Apple-owned example files.

Their actual contents are mostly formatting, i.e. they look like
something created specifically to be a test case for reading formatting,
or possibly a documentation example for formatting but the above makes
that less likely, not something copied from real-world use.

Given this, why is that copyright notice there, and what does it imply
that we should do? (E.g. does Apple Numbers automatically copy
Apple-owned items (e.g. fonts) into files it creates? If so, is there a
way to remove these items to get a Free file?)