Comment 2 for bug 1978340

This seems to happen when I mount something to /mnt before running flatpak:

$ sudo guestmount -a livecd.ubuntu-cpc.ec2-hvm-ebs.vmdk -i --ro /mnt
[sudo] password for tom:
$ flatpak run org.gnome.gitg
bwrap: Can't get type of source /mnt: Permission denied
error: Failed to sync with dbus proxy