Last I checked Trojita was beautiful but cursed with the limitation of only supporting one email account. It looks like it's still that way.
The whole point of me using an email client instead of a webmail interface is so that I can manage multiple email accounts. I'm not sure what other advantages there could possible be, unless the web interface is particularly bad.
Wow I remember looking into that back in... 2010. At that time I was making my own Qt email client, called BetterInbox (now defunct), and was looking at Trojita for examples on how to do things. I was also an active KDE contributor, and wrote an SMTP library (which amazingly still lives on, now at https://github.com/KDE/ksmtp)
All the buttons on the left are icon-only and unlabeled. Maybe there's an option to show labels, and there are probably tooltips. But I'm bored and I want to make a point, so this is my attempt to determine what the icons mean as if I were a user looking at this for the first time:
(from top to bottom)
1. (Pencil) Compose a new email. Straightforward.
2. (Envelope with green dotted arrow pointed left) Is this... retrieve mail from server? And the one below it is send mail that's in the outbox? Oh, nevermind, this is probably "Reply", because I bet the dropdown arrow is to pick "Reply all".
3. (Envelope with purple solid arrow pointing right) This is probably forward, since the one above is "Reply all". And this one doesn't have a dropdown arrow, which would make sense. I'm not sure why the arrow colors are different, or why one is solid and the other dotted.
4. (Trash bin) Okay, this is delete. Straightforward.
5. (Tray with a letter sticking out). Not sure about this one, I have no idea what this represents -- but it seems to have a selected state in the screenshot, so maybe this is a "Mark read/unread" button?
6. (Cancel symbol) This one is tricky. We already have a pretty clear "delete" button with the trash bin. Maybe this is to mark as junk?
7. (Flag) Okay, this is flag/unflag. Pretty clear.
8. (Envelope with a cancel symbol). Ehh. Not sure what this is. We already had another "cancel" button. The button below this one is an envelope with a green checkmark, so this is probably the opposite action of that one. Maybe this is "mark as junk" and the checkmark is "un-mark as junk"? But then what's button #6?
9. (Envelope with green checkmark). See above.
10. (Connection symbol (?)). Guessing this is related to going online/offline, or manually checking for mail?
11. (Hamburger). It's a hamburger, so who knows. I guess it's where you access settings and other configuration details.
To be clear, this might be a very well-crafted piece of software, and I have a ton of respect for any open-source desktop software. Icons can be hard to get right, especially if you're an engineer and don't have UX experience. But even as someone who's pretty tech-savvy and familiar with how email works, it took a lot of deduction to figure out what those icons mean — and I'm still not sure on a few of them.
The whole point of me using an email client instead of a webmail interface is so that I can manage multiple email accounts. I'm not sure what other advantages there could possible be, unless the web interface is particularly bad.