The nanos *are* hard to describe non-confusingly - resisting the urge to
fix more globally.
--- a/src/java.base/share/classes/java/time/Instant.java
+++ b/src/java.base/share/classes/java/time/Instant.java
@@ -610,7 +610,7 @@
* <p>
* The epoch second count is a simple incrementing count of seconds
where
* second 0 is 1970-01-01T00:00:00Z.
- * The nanosecond part of the day is returned by {@link #getNano}.
+ * The nanosecond part is returned by {@link #getNano}.
*
* @return the seconds from the epoch of 1970-01-01T00:00:00Z
*/
