I have noticed that email types in Administration -> E-Mails are not translated:

I have noticed that email types in Administration -> E-Mails are not translated:

This one is a bit trickier, but here’s what I found out.
EmailLog records, which have an email_type field defined here:EmailLog records are created in the jobs NotifyMailingListSubscribers and UserEmail.UserEmail jobs (and CriticalUserEmail jobs, which are a subtype) are queued at different locations with mostly hardcoded email types (found via grep -R "user_email" .):signup and signup
account_created
forgot_password
admin_login and signup
digest
mailing_list
signup_after_approval
signup
user_email
account_created
notify_old_email
confirm_new_email, confirm_old_email and confirm_new_email once more via this helper method
Email::Sender.new(...) (which creates an EmailLog here), namely (as indicated by grep -R "Email::Sender.new" .):
digest
invite
invite_password_instructions
mailing_list
test_message
new_version
pending_queued_posts_reminder
email_reject_*
subscription
(This should be it.)
In general, it would be a good idea to collect the complete list of valid email types (not to be confused with the email template types) at a central place and make these translatable (even though plugins may send emails as well, I suppose, therefore we probably cannot reject email keys that are not in this list, which would assert that this list is to be kept complete).
I’m also curious about all possible email_types, because I’m looking into disabling certain email types.
So far, I’ve seen:
signup
forgot_password
mailing_list
test_message
But the code also shows more unusual ones like blah.
List of types: