If you are interested on testing and giving feedback of this feature all the works are going on this branch:

https://github.com/stdevPavelmc/mailad/tree/stdevPavelmc_t178_webmail

Just clone it and give it a try, feedback channel is on the Issue https://github.com/stdevPavelmc/mailad/issues/178 or via the Dev Telegram channel: https://t.me/MailAD_dev

All feedback are welcomed!