Agree. I'd like to have the possibility to change some to each account - color or label or icon. Because we can not manage yet comfortably those without trying.
I would like to be able to assign different colours to accounts in the message pane, similar to the function offered in old Thunderbird versions by the extension "Account Colors" by DW-dev.
Yes, this will be useful. I've stayed at an earlier version of Thunderbird just to have Account Colors, which does not work with the latest versions of Thunderbird.
Great news! This feature is now in development, and we're aiming to ship it in time for Thunderbird 128 in July. This is the first patch of an upcoming stack that will add some nice visual cues in the message list and the compose window for users with multiple accounts.
Keep your feedback and suggestions coming, we appreciate it!
Yes, this is good news! The deprecated addon Account Colors should serve as a good start. I would think with access to the actual code you should have the opportunity to make it nice, but still clean.
Hopefully, in the new versions you don't remove more functionality.