If somebody wants to backup such folders then what is needed is giving shell used to run restic full disk access. It is really simple like that. Give your bash or zsh or whatever you are using full disk access and use restic to backup anything:)
Or going more complicated route and packaging restic as some signed app (probably too much for most users).
But it only solves part of the problem. To do this well you should also incorporate APFS snapshots. It is great to use Thunderbird (I use it myself) but without filesystem snapshots its profile backup consistency is pure lottery.
Or in other words - restic is fantastic program to backup files. But plenty of extra things have to be taken care of before it forms part of proper backup solution. I am not aware of single FOSS one for macOS. Unfortunately all are paid only - I refrain from advertising here. Who needs it can google options in seconds.
~/Library is definitely not a system folder but macOS’ security mechanisms restrict access to it like it was one. But the real trouble starts, imho, with the way Apple software stores its data and with all the complicated mechanisms in the background. Some of them sure might be nice to use but I find the system increasingly hard to handle - at least outside the paths provided by Apple.
…and that’s exactly what I do. Mentioned it in my first comment itself “However what still works is: temporarily giving permission… “
Thunderbird (I use it myself) but without filesystem snapshots its profile backup consistency is pure lottery.
I am coming back to TB having used it on Linux back in the day (but only a bit; back then I was more of an Evolution Man). I am trying to finalise my TB setup and then also try to learn a bit on mailbox archive/file types. It’s MBOX for TB right? Can I change it; that one that will be better for deduping+compressing backup tools and possibly also good for my human eyes when I need to access them and isn’t an absolute mess like Apple’s Mail.app’s format. But I think mbox’es are essentially giant text files so easy for backup tools, right? (If you don’t mind please do share some resources/tutorials if you have on it). (I had seen http://betterbird.eu mentioned somewhere - never used it).
I actually like Apple Mail:) and use it exclusively as my daily email tool.
But I found it hard to deal with emails backup so I have also installed TB. I do not use it really. It starts automatically at night to sync all emails followed by restic run to backup its full profile. I love that I can then use the same profile on Linux or Windows in even offline mode to access all my emails.
I have never looked at details how TB stores data - because frankly I do not need this knowledge:) It is enough for me that I can restore and access all my email on any system. It is only at the end what I care about - in case of some disaster to be able to read some very important email I received 2 years ago.
In addition if one day I have to do more with it I am also sure it will be easier than dealing with Apple Mail backup. TB is open source at the end with still large user base and active community.
I used to love it a lot as well back in the olden days.
I have a customer with about 12 people on Macs using around 20 mailboxes and had to do a mail server move the other day. Now the little hairs on my neck stand up every time I even only read “Apple Mail”. It’s gotten so buggy I don’t even know where to start complaining.
TB is boring, a little overloaded and not very beautiful. But I can handle it and it mostly does what it’s supposed to.
