diff --git a/src/libexpr/get-drvs.hh b/src/libexpr/get-drvs.hh
index b886581b6..e8c1190f7 100644
--- a/src/libexpr/get-drvs.hh
+++ b/src/libexpr/get-drvs.hh
@@ -10,7 +10,9 @@
 
 namespace nix {
 
-
+/**
+ * A "parsed" package attribute set.
+ */
 struct PackageInfo
 {
 public:
diff --git a/src/libstore/builtins/buildenv.hh b/src/libstore/builtins/buildenv.hh
index 8bebd390d..b24633e27 100644
--- a/src/libstore/builtins/buildenv.hh
+++ b/src/libstore/builtins/buildenv.hh
@@ -5,6 +5,9 @@
 
 namespace nix {
 
+/**
+ * Think of this as a "store level package attrset", but stripped down to no more than the needs of buildenv.
+ */
 struct Package {
     Path path;
     bool active;