What I’m talking about is replacement string. Replace string is a term for a string that replaces a broken string. In this case, replace string would be the replacement of a string that has a broken end.
For example, take a string that has two broken ends. One ends at (a, b). Replace it with (a, b, c), which has the same number of broken ends, but the middle broken part is now a short string. And now you have a broken string that can be used in place of the broken string.