* theory.html: Source data can do subseconds.

theory.html

@@ -723,8 +723,8 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes
     than what the <code><abbr>tz</abbr></code> code can handle.
     For example, from 1880 to 1916 clocks in Ireland observed Dublin Mean
     Time (estimated to be <abbr>UT</abbr>
-    &minus;00:25:21.1), but the <code><abbr>tz</abbr></code>
-    code cannot represent the fractional second.
+    &minus;00:25:21.1); although the <code><abbr>tz</abbr></code>
+    source data can represent the .1 second, TZif files and the code cannot.
     In practice these old specifications were rarely if ever
     implemented to subsecond precision.
   </li>