About LISCENSE of the code

ComputeBlockMapping a block is represented in a string the function computes the result is a mapping from each index in new to its counterpart in old, -1 if new.

Delete is the operation kind for a line that is present in the input but not in the output.

Equal is the operation kind for a line that is the same in the input and output, often used to provide context around edited lines.

Insert is the operation kind for a line that is new in the output.

OpKind is used to denote the type of operation a line represents.