private String relativize(Path parent, String anchorTarget) {
		Path anchorPath = Paths.get(anchorTarget);
		if (anchorPath.isAbsolute()) {
			return anchorTarget; // not a relative path; nothing to do
		}

		if (!parent.endsWith("help")) {
			throw new AssertException("Map file expected in a directory name 'help'.  " +
				"Update the map file generation code.");
		}

		if (!anchorTarget.startsWith("help")) {
			throw new AssertException("Relative anchor path does not start with 'help'");
		}

		Path relative = anchorPath.subpath(1, anchorPath.getNameCount());
		String relativePath = relative.toString();
		String normalized = relativePath.replaceAll("\\\\", "/");
		return normalized;
	}
This class:
<ul>
     <li>Creates a XXX_map.xml file (topic IDs to help files)</li>
     <li>Creates a XXX_TOC.xml file from a source toc.xml file</li>
     <li>Finds unused images</li>
</ul>
Ghidra/Framework/Help/src/main/java/help/JavaHelpFilesBuilder.java