Basic types Point and WitnessSet are defined in the package NAGtypes.
Version 1.4 of this package was accepted for publication in volume 3 of the journal The Journal of Software for Algebra and Geometry: Macaulay2 on 2011-05-20, in the article Numerical Algebraic Geometry. That version can be obtained from the journal or from the Macaulay2 source code repository, after installing subversion, with the following shell command:
svn export -r 13254 svn://svn.macaulay2.com/Macaulay2/trunk/M2/Macaulay2/packages/NumericalAlgebraicGeometry.m2
The following command will display the log messages accompanying any changes to the file in the repository since publication.
svn log -r 13255:HEAD svn://svn.macaulay2.com/Macaulay2/trunk/M2/Macaulay2/packages/NumericalAlgebraicGeometry.m2
The following command will summarize the changes to the file in the repository since publication, in the format the program diff uses: lines starting with + have been added, and lines starting with - have been removed. (Changes to white space or end of line style will not be reported.)
svn diff -x "-b --ignore-eol-style" -r 13254:HEAD svn://svn.macaulay2.com/Macaulay2/trunk/M2/Macaulay2/packages/NumericalAlgebraicGeometry.m2
The differences between two releases in the repository mentioned in the log can be displayed by replacing 13254:HEAD by the pair of release numbers separated by a colon.