2.1.1631 Part 1 Section 126.96.36.199, baseJc (Matrix Base Justification)
a. The standard says that baseJc applies only to matrices even though the schema allows it as a child of equation arrays.
In Word, baseJc applies to matrices and equation arrays.
b. The standard does not specify in detail how to align the matrix with the surrounding content.
Word uses baseline alignment to align the matrix with the surrounding content.