Program getFirstProgram() {
		return primaryProgram;
	}
Get the first program for the current Diff. <br>
<b>Note</b>: This may not be the currently active program.

@return the Diff's first program or null if don't currently have a second program associated
        for a Diff.
Ghidra/Features/ProgramDiff/src/main/java/ghidra/app/plugin/core/diff/ProgramDiffPlugin.java