public String getErrorMessage() {
		return errorMsg.toString();
	}
Get the error messages that resulted from the last call to a merge or
replace method. These are errors that prevented something from being merged.
<br>Important: Call clearErrorMessage() to clear the current error message after this returns it.
@return the error message string or an empty string if there were no problems with the merge.
Ghidra/Features/Base/src/main/java/ghidra/program/util/ProgramMerge.java