This is what is returned by the FindMath class, giving the location
of math within the document, and is used to produce the full
MathItem later (e.g., when the position within a string array
is translated back into the actual node location in the DOM).
The ProtoItem interface
This is what is returned by the FindMath class, giving the location of math within the document, and is used to produce the full MathItem later (e.g., when the position within a string array is translated back into the actual node location in the DOM).