Send out mail with full name of commenter
The Ruby core team uses Redmine for issue tracking (see https://bugs.ruby-lang.org). The source for this Redmine instance is maintained at https://github.com/ruby/b.r-l.o/. Mails from this instance seem to only use the login name if there are non-ASCII characters in the full name. If the full name does not contain non-ASCII characters, then both the login name and the full name are given.
Analyzing the problem lead to the conclusion that this is a Redmine issue, not specific to bugs.ruby-lang.org. That's why I'm reporting it here. I'm not familiar with the internals of Redmine, but for example the 'mail' gem has no problem sending out mails with non-ASCII names.