Answer prose round 1: errNoData, the reads paragraph and the changelog entry read in one pass, the Library section shows the import block for one locale, and the decisions state why New checks no reads and which goal the embed serves

data.go

@@ -8,7 +8,8 @@ import (
 
 // loadSources merges sources in order, the last winning a clash. A source whose manifest
 // carries an index leaves its categories unloaded; every other source loads here, with
-// the unloaded categories it needs: docs/decisions.md#a-source-whose-manifest-carries-an-index-loads-each-category-on-first-reach-any-other-loads-in-new-with-what-it-reads
+// the unloaded categories it needs.
+// docs/decisions.md#a-source-whose-manifest-carries-an-index-loads-each-category-on-first-reach-any-other-loads-in-new-with-what-it-reads
 func loadSources(sources []datafiles.Source) (folder, error) {
 	root := folder{children: map[string]node{}}
 	walked := map[string][]string{}
@@ -24,8 +25,8 @@ func loadSources(sources []datafiles.Source) (folder, error) {
 	return root, loadReached(&root, sites, nil)
 }
 
-// addSource places src's categories in root, and sets in walked, for each category it loads
-// here, the modules src reads by default.
+// addSource places src's categories in root. For each category it loads now, it records in
+// walked the modules src reads by default.
 func addSource(root *folder, src datafiles.Source, walked map[string][]string) error {
 	m, err := src.Manifest()
 	if err != nil {