I think this,
$ LC_TIME=zh_TW.UTF-8 date
西元2020年11月18日 (週三) 12時39分44秒 CST
should say 公元 not 西元.
Alas, I do not know where to submit this bug to.

* 積丹尼 Dan Jacobson:

Why do you think so?  These Taiwanese newspapers appear to use 西元
for Gregorian years:

  <https://www.chinatimes.com/hottopic/20191108002189-260809?chdtv>
  <https://udn.com/umedia/story/12749/5023798>

Is there a difference between calendar dates and historical
references?

We just like one does not want to mention "Christ" when talking about
https://en.wikipedia.org/wiki/Metric_time etc.
See also
https://zh.wikipedia.org/wiki/公元
FW> * 積丹尼 Dan Jacobson:

FW> Why do you think so?  These Taiwanese newspapers appear to use 西元
FW> for Gregorian years:

FW>   <https://www.chinatimes.com/hottopic/20191108002189-260809?chdtv>

Actually that only uses it once. But uses an unadorned 2020 many times.
Likewise in:

FW>   <https://udn.com/umedia/story/12749/5023798>

FW> Is there a difference between calendar dates and historical
FW> references?

Even if there was, the date(1) command could only choose one.

And that one should be the one without silly "east" and "west"
connotations.

retitle 975026 Don't add "西元" to worldwide (2020) dates!
thanks

In fact I got a much better idea:

Chuck the whole 西元 totally!

Does
$ LC_ALL=C date
Thu Nov 19 13:11:20 CST 2020
add "A.D." etc.? No!

Anyway, it is up to
https://en.wikipedia.org/wiki/North_Korean_calendar
https://en.wikipedia.org/wiki/Republic_of_China_calendar
usages to put special names on their years.

For everybody else, 2020 should just be 2020!

Just like

FW>   <https://www.chinatimes.com/hottopic/20191108002189-260809?chdtv>

Actually that only uses 西元 once. But uses an _unadorned_ 2020 many times.