Hey! I don't use Linux myself, but we have a ton of Linux users playing the game without issues, so I've asked around to see if anyone knows how to solve this. Will get back to you!
Someone on our Discord channel had the same problem and managed to resolve it for him or her.
The files missing are part of the auto-update. That person's theory is that if you're behind a firewall or VPN, the connection to Google can get denied denied (the game files are located on Google Drive). So the proper files don't get downloaded, and thus the game crashes.
When that person is on VPN the fresh download crashes, but it works fine when the person disconnects his or her VPN.
It could be that, i was on vacation and there was quite terrible connectivity. (no vpn used there)
But now i've retried again at home, and it does the same. Although this time i do have vpn active for work, but i would say correctly configured for only specific ips/dns to go through vpn, regular traffic/dns goes to my local router.
Just few empty .tmp files appears in _Data folder, but that's all.
-> % ll fertile_crescent/The\ Fertile\ Crescent\ Launcher_Data total 3.1M
...
drwx------. 2 queria queria 4.0K Jun 17 00:19 Resources
drwx------. 2 queria queria 4.0K Jun 17 00:20 loc
-rw-rw-r--. 1 queria queria 0 Aug 5 13:28 4ed73eac-c9ed-4a86-a0c5-7b69c7cc3528.tmp
-rw-rw-r--. 1 queria queria 38 Jun 17 00:19 app.info
-rw-rw-r--. 1 queria queria 0 Aug 4 16:27 b80647d2-82b2-4132-b5c5-d08c581e8bdf.tmp
-rw-rw-r--. 1 queria queria 123 Jun 17 00:19 boot.config
-rw-rw-r--. 1 queria queria 45K Jun 17 00:19 globalgamemanagers
...
How can i gather more info?
Is there a log file somewhere, some status files, or some url for me to test fetching (e.g. with curl or such)?
Btw i've just tested it on my desktop machine, where i had the game already from previous versions working, seems updating there works (it did some fetching&patching).
So seems as some bad state on the laptop? How exactly is vpn known to cause the issue?
We've had several cases of people with your problem who resolved it by disabling VPN or firewall. The game files are located on Google Drive, and if you're using VPN, Google might think you're an "uncertified" user and restrict access. The game files get downloaded to The Fertile Crescent_Data, so if there's nothing there, it means the launcher wasn't able to fetch the game files.
In the distant future, we'll probably release the game on Steam, and then not have the current launcher anymore. But for now it's very useful since it makes it easier for us to patch the game, and you don't have to manually download (and check for) the latest version. :)