DEBUG: This is the tool I used to re-generate the root-manifest file,…

… altered slightly from a0a6349

docs/generate.php

@@ -0,0 +1,119 @@
+<?php
+/**
+ * Usage: `cd gutenberg/docs && php generate.php`
+ * PHP 7.1+ recommended
+ */
+ /**
+ * Get the markdown title from the first h1 tag, e.g. `# text`
+ *
+ * @param string $contents
+ *
+ * @return string
+ */
+function getTitle(string $contents = '')
+{
+	// Attempt to extract a title
+	if (preg_match('/^#\s(.+)/m', $contents, $matches)) {
+		$title = $matches[1];
+	}
+ 	return $title ?? null;
+}
+ /**
+ * Get a slug from the given file path
+ *
+ * @param string $filePath
+ *
+ * @return string
+ */
+function getSlug(string $filePath)
+{
+	// Get the file path
+	$path = __DIR__ . '/../' . $filePath;
+ 	// Get the markdown file name
+	$fileName = basename($path, '.md');
+ 	// Get the appropriate file path
+	$slug = ($fileName === 'README' || $fileName == 'readme' ) ? basename(dirname($path)) : $fileName;
+	return ( 'docs' == $slug ) ? 'handbook' : $slug;
+}
+ /**
+ * Get the "parent" setting. The parent a docs-relative path to the
+ * containing folder (or null, if it is a top-level item)
+ *
+ * @param string $filePath
+ *
+ * @return string
+ */
+function getParent(string $filePath)
+{
+	// Sanitises the path string
+	$path = str_replace(
+		[
+			__DIR__ . '/../docs/',
+			'.md',
+			'/readme',
+			'/README',
+		],
+		'',
+		$filePath
+	);
+ 	// If a slash exists in the path...
+	if (stripos($path, '/')) {
+		// Explode the path into path segments
+		$segments = explode('/', $path);
+ 		// Pop the last item off the array of segments
+		array_pop($segments);
+ 		// Implode it again and use it as the $parent
+		$parent = basename( implode('/', $segments) );
+	}
+ 	return $parent ?? null;
+}
+ /**
+ * Process a table-of-contents array into a manifest file
+ *
+ * @param array $level
+ *
+ * @return array
+ */
+function process(array $level)
+{
+	$manifest = [];
+ 	foreach ($level as $i => $child) {
+		foreach ($child as $file => $children) {
+			// Build an absolute path to the file
+			$path = __DIR__ . '/../' . $file;
+ 			// Append to the manifest
+ 			$title = getTitle(file_get_contents($path));
+ 			if ( ! $title ) {
+ 				$title = ucwords( basename( $path ) );
+ 				if ( 'Readme.md' == $title ) {
+ 					$title = ucwords( basename( dirname( $path ) ) );
+ 				}
+ 			}
+			$manifest[] = [
+				'title'           => $title,
+				'slug'            => getSlug($file),
+				'markdown_source' => sprintf('https://raw.githubusercontent.com/WordPress/gutenberg/master/%s', $file),
+				'parent'          => getParent($path),
+			];
+ 			// Run the process for children items
+			if (!empty($children) && is_array($children)) {
+				$additions = process($children);
+ 				// Merge the children into the containing manifest
+				$manifest = array_merge($manifest, $additions);
+			}
+ 			if (is_string($children)) {
+				// @todo
+				// The TOC.json format includes tokens that could be replaced
+				// in the future, for easily embedding auto-generated content
+				// into the overall manifest.
+			}
+		}
+	}
+ 	return $manifest;
+}
+ // Decode the TOC JSON
+$contents = json_decode(file_get_contents(__DIR__ . '/toc.json'), true);
+ // Process the contents
+$response = process($contents);
+ // Push out to root-manifest.json
+file_put_contents(__DIR__ . '/root-manifest.json', json_encode($response, JSON_PRETTY_PRINT));