I was getting a 404 because it was looking for en_us, not just en. The en template may need to be copied for other English locales like en_GB, en_CA, etc. The 404 only showed up in Firefox's developer console did not appear to affect functionality, so this is just cleanup.

wise-webapp/src/main/webapp/js/jquery.timeago.en_us.js

@@ -0,0 +1,20 @@
+// English (US)
+jQuery.timeago.settings.strings = {
+  prefixAgo: null,
+  prefixFromNow: null,
+  suffixAgo: "ago",
+  suffixFromNow: "from now",
+  seconds: "less than a minute",
+  minute: "about a minute",
+  minutes: "%d minutes",
+  hour: "about an hour",
+  hours: "about %d hours",
+  day: "a day",
+  days: "%d days",
+  month: "about a month",
+  months: "%d months",
+  year: "about a year",
+  years: "%d years",
+  wordSeparator: " ",
+  numbers: []
+};