hgrc.5: whether bcc is prompted for is up to the extension
There is no code in mail.py that forbids an extension to prompt for bcc.
--- a/doc/hgrc.5.txt Sat Jan 23 02:03:42 2010 +0100
+++ b/doc/hgrc.5.txt Thu Jan 28 10:38:29 2010 +0000
@@ -305,7 +305,7 @@
email addresses.
``bcc``
Optional. Comma-separated list of blind carbon copy recipients'
- email addresses. Cannot be set interactively.
+ email addresses.
``method``
Optional. Method to use to send email messages. If value is ``smtp``
(default), use SMTP (see the SMTP_ section for configuration).