Seems like biased towards some bands, while omitting some arguably greater or at least equally important bands of the same era. Not that there's anything wrong with Yes or Jethro Tull being mentioned, but if they are, seems like Genesis and King Crimson should be mentioned as well.
$ cat /usr/share/calendar/calendar.music | grep Genesis
$ cat /usr/share/calendar/calendar.music | grep "King Crimson"
$ cat /usr/share/calendar/calendar.music | grep Yes
02/20 Yes sells out Madison Square Garden...without advertising, 1974
04/18 Yes breaks up after 13 years, 1981
10/25 Jon Anderson (Yes) is born in Lancashire, England, 1944
$ cat /usr/share/calendar/calendar.music | grep "Jethro Tull"
08/10 Ian Anderson (Jethro Tull) is born in Edinburgh, Scotland, 1947