diff --git a/src/runtime.c b/src/runtime.c
index 21201073fcd843bfff521491d75248f12906bfff..df79beedffd7bf3cc522979575b9633863ad9a43 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -682,7 +682,10 @@ typedef struct
    * or (type SrtVaApiDriver) */
   gpointer icd;
   gchar *resolved_library;
-  /* Last entry is always NONEXISTENT */
+  /* Last entry is always NONEXISTENT.
+   * For VA-API, we use [0] and ignore the other elements.
+   * For the rest, this is keyed by the index of a multiarch tuple
+   * in multiarch_tuples. */
   IcdKind kinds[G_N_ELEMENTS (multiarch_tuples)];
   /* Last entry is always NULL */
   gchar *paths_in_container[G_N_ELEMENTS (multiarch_tuples)];