/usr/share/doc/mlton/examples/callcc.sml is in mlton-doc 20100608-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | open MLton.Cont
val _ = print(Int.toString(1 + callcc(fn k => throw(k, 2))))
val _ = print "\n"
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