How to make Thunderbird understand local .maildir folder?

It's been some (relatively short) time since Thunderbird finally obtained maildir storage support (I'm using Thunderbird 38.1.0 at the time of this writing). Unfortunately it appears it only applies to how Thunderbird itself stores mail internally, e.g. for IMAP/POP3 accounts. What I wish though, is to be able to read the contents of a typical /home/user/.maildir directory that contains mail locally delivered for a user (as an alternative to /var/spool/mail style delivery).

Now, the best idea I've come up with is symlinking a specially-created-for-the-purpose Inbox folder from Thunderbird's 'Local Folders' account to it, but Thunderbird seems to be unable to even notice the mail in it, Inbox appears empty (not even a restart helps).

I of course can revert to setting up a Thunderbird's movemail account with /var/spool/mail (after reconfiguring exim, which does local mail delivery, appropriately), but I honestly wish to not need to.

As additional information for those wondering this same thing (which I had explored over this past summer for Thunderbird 60.8.0) I thought I would share the following, as I was hoping to couple my Thunderbird's maildir setup with mutt.

From a note in Mozilla's Support regarding Thunderbird and maildir:

Note – this is NOT full Maildir in the sense that most users, particularly Linux or mail administrators, know Maildir. You cannot point Thunderbird accounts to a mail server directory, nor do you get message flags stored with emails. See the wiki for more details

https://support.mozilla.org/en-US/kb/maildir-thunderbird

https://wiki.mozilla.org/Thunderbird/Maildir

They do not state why this is so, just that it is so.

A check on the diffs between the headers of the emails are as follows.

Mutt, with vdirsyncer and offlineimap

< Return-Path: <[email protected]>
…

Thunderbird

> From - Fri Jul 26 21:00:32 2019
> X-Mozilla-Status: 0001
> X-Mozilla-Status2: 00000000
> X-Mozilla-Keys:                                                                                 
> Return-Path: <[email protected]>
…

Also, Thunderbird inserted a blank line at the bottom of its copy of the email.