Person asked about same issue only 30 minutes before making another question, so I suggest all answers be keep in one location to maintain continuity if conversation and not waste time repeating anything: https://support.mozilla.org/en-US/questions/1550475

Hello

For information purposes. A space for users to give product feedback. https://support.mozilla.org/en-US/kb/what-mozilla-connect

https://connect.mozilla.org/t5/ideas/color-for-thunderbird-accounts/idi-p/14758

https://connect.mozilla.org/t5/ideas/correos-en-colores-mail-in-colors/idc-p/63337

I see that the other post is about colors. This one also asks about general experiences. So I will respond to that inquiry here.

No porting is needed. The two apps use the same user profile. When I tried Betterbird and then switched back to Thunderbird, my profile had problems. I had to re-create it.

I decided to stay with Thunderbird because I did not see significant advantages of Betterbird, Mozilla has more resources, and I do not want more profile problems.

Apparently, current Series: Betterbird 140.

Thunderbird release notes. https://www.thunderbird.net/en-US/thunderbird/releases

Allow me this illustration. I launched Thunderbird release 115 and Thunderbird beta 125. I opened the two profiles. I stopped the two versions of Thunderbird. I deleted the contents Thunderbird release 115 profile folder. I copied the contents from beta profile folder, and, pasted into Thunderbird release 115 profile. I launched Thunderbird release 115 "Vous avez lancé une ancienne version de Thunderbird", i chose Quitter and i deleted the compatibility.ini file, and I launched Thunderbird release 115.

https://www.youtube.com/watch?v=lrm-JElL6IQ

Source of information. https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation

is explained in the Firefox article Understanding in depth the profile

https://support.mozilla.org/en-US/kb/understanding-depth-profile-installation

It would seem my request to keep all conversation in the original question has not transpired. Maybe there was some confusion.

Thunderbird 'mail account name' as displayed in the Folder Pane, has a colour dependent upon the theme being used. eg: white in a dark theme.

When the account receives new mail, that 'mail account name' changes colour to display/draw your attention to the account that has received new mail.

If mail account has unread mail (but not new -as you have accessed it since last download) then the font with be 'bold' to indicate unread mail.

Whilst I can use the 'userChrome.css' to change the colour of the font used for all folders in the Folder pane, I've not yet located info on how to specifically alter colour for a specific mail account name.

It would seem my request to keep all conversation in the original question has not transpired. Maybe there was some confusion.

Well, I don't know about other people, but, as I said, different questions were posed in different discussions. I responded about Betterbird in the discussion that was about Betterbird. The other discussion is specifically about colors.