protected ResourceFile findGhidraApplicationInstallationDir() {
		if (applicationRootDirs.isEmpty()) {
			return null;
		}

		ResourceFile dir = applicationRootDirs.iterator().next().getParentFile();
		if (SystemUtilities.isInDevelopmentMode() && applicationRootDirs.size() > 1) {
			dir = dir.getParentFile();
		}
		return dir;
	}
Finds the application installation directory for this Ghidra application
layout.

@return The application installation directory for this Ghidra
        application layout. Could be null if there is no application
        installation directory.
Ghidra/Framework/Utility/src/main/java/ghidra/GhidraApplicationLayout.java