Add ratarmount
Some permissions are wrong; cannot run in Firejail as a result:

Why is the CI green even though you report the permission error?
I have no idea what could be wrong. Do you have any idea, maybe from other projects with similar issues that have been resolved?
First off, I cannot even reproduce the error.
Running firejail ... gives me:
Reading profile /etc/firejail/default.profile
Reading profile /etc/firejail/disable-common.inc
Reading profile /etc/firejail/disable-programs.inc
** Note: you can use --noprofile to disable default.profile **
Parent pid 3886306, child pid 3886307
Child process initialized in 55.64 ms
fuse: failed to exec fusermount: Permission denied
Cannot mount AppImage, please check your FUSE setup.
You might still be able to extract the contents of this AppImage
if you run it with the --appimage-extract option.
See https://github.com/AppImage/AppImageKit/wiki/FUSE
for more information
open dir error: No such file or directory
Parent is shutting down, bye...
Running firejail --noprofile ... works without issue. No idea which setting leads to the error above:
Parent pid 3888012, child pid 3888013
Child process initialized in 4.95 ms
usage: ratarmount.py [-h] [-c] [-r] [-u] [-P PARALLELIZATION] [-v] [--password PASSWORD] [--verify-mtime] [--index-file INDEX_FILE] [--index-folders INDEX_FOLDERS]
[--recursion-depth RECURSION_DEPTH] [-l] [-s] [--transform-recursive-mount-point REGEX_PATTERN REPLACEMENT] [-e ENCODING] [-i] [--gnu-incremental]
[--no-gnu-incremental] [-w WRITE_OVERLAY] [--commit-overlay] [-o FUSE] [-f] [-d DEBUG] [-gs GZIP_SEEK_POINT_SPACING] [-p PREFIX]
[--password-file PASSWORD_FILE] [--use-backend USE_BACKEND] [--oss-attributions]
mount_source [mount_source ...] [mount_point]
ratarmount.py: error: the following arguments are required: mount_source
Parent is shutting down, bye...
I tried to download the AppImage from the releases page, add execute permission and reupload it but it doesn't change the execute permissions when downloading. It was the wrong thought anyway because the problem stems from AppRun, not the .AppImage file.
The only issue I can think of is that the AppRun is a shell script with this shebang #! /bin/bash. And a bash binary is not shipped with the AppImage, so maybe your /bin/bash does not have the correct execute permissions?
I have now tried to redirect the shebang to dash and I have bundled a dash binary into the AppImage. Would you be so kind to check whether that fixes the issue so that I can merge it upstream and do a new release?
Why is the CI green even though you report the permission error?
I've been wondering the exact same thing since a veeery long time...
I have now tried to redirect the shebang to dash and I have bundled a dash binary into the AppImage. Would you be so kind to check whether that fixes the issue so that I can merge it upstream and do a new release?
I can run a test if you can upload it unzipped somewhere (GitHub Artifacts unfortunately can't do that). E.g., you can manually upload it to GitHub Releases.
I have now tried to redirect the shebang to dash and I have bundled a dash binary into the AppImage. Would you be so kind to check whether that fixes the issue so that I can merge it upstream and do a new release? ratarmount.AppImage.zip
I can run a test if you can upload it unzipped somewhere (GitHub Artifacts unfortunately can't do that). E.g., you can manually upload it to GitHub Releases.
https://github.com/mxmlnkn/ratarmount/raw/appimagehub/ratarmount-0.13.0-with-dash-experimental.AppImage
The output without any argument is:
/bin/bash
lrwxrwxrwx 1 user group 0 Jun 18 13:56 /proc/2132468/exe -> /usr/bin/dash
-rwxr-xr-x 1 root root 125688 Mar 23 2022 /usr/bin/dash
usage: ratarmount.py [-h] [-c] [-r] [-u] [-P PARALLELIZATION] [-v] [--password PASSWORD] [--verify-mtime] [--index-file INDEX_FILE]
[--index-folders INDEX_FOLDERS] [--recursion-depth RECURSION_DEPTH] [-l] [-s]
[--transform-recursive-mount-point REGEX_PATTERN REPLACEMENT] [-e ENCODING] [-i] [--gnu-incremental] [--no-gnu-incremental]
[-w WRITE_OVERLAY] [--commit-overlay] [-o FUSE] [-f] [-d DEBUG] [-gs GZIP_SEEK_POINT_SPACING] [-p PREFIX]
[--password-file PASSWORD_FILE] [--use-backend USE_BACKEND] [--oss-attributions]
mount_source [mount_source ...] [mount_point]
ratarmount.py: error: the following arguments are required: mount_source
I.e. /proc/self/exe should use dash.
Looks like https://github.com/mxmlnkn/ratarmount/raw/ ... is not supported by the test?
In any case, we cannot expect /usr/bin/dash to be on each target system. /bin/sh would be a safer bet.