New comment by leahneukirchen on mblaze repository https://github.com/leahneukirchen/mblaze/issues/210#issuecomment-859450672 Comment: In mblaze-profile(5): ``` Outbox: If set, mcom(1) will create draft messages in this maildir, and save messages there after sending. ``` If you sync this with your provider it probably does what you want. But e.g. GMail (and Fastmail, if you enable it), feature saving all SMTP sent mails server side. This is outside of mblaze's control.