Merge branch 'dev' into f-refactor-serialization

caosdb-webui @ 7d67a76f

-Subproject commit b6677e848ed30cadeda5d1782bd4376ec6546031
+Subproject commit 7d67a76f1ceede440a2d4dad4db8dcbd0d61b9ed

src/main/java/caosdb/datetime/UTCDateTime.java

@@ -162,6 +162,13 @@ public class UTCDateTime implements Interval {
     addLeapSecond(gc.getTimeInMillis() / 1000);
   }
 
+  /**
+   * Initialize the container with known leap seconds. This container has to be updated according to
+   * future changes of leap seconds.
+   *
+   * <p>Currently all leap seconds between 1972 and 2019 are registered here, with the most recent
+   * leap second being added for December 2016.
+   */
   private static void initLeapSeconds() {
 
     // june 1972