Sandbox default mounts
Sandbox path	Host source	Notes
/usr /bin /sbin /lib /lib32 /lib64	/usr /bin /sbin /lib /lib32 /lib64	read-only
/etc	/etc overlay base layer	read-only overlay
	~/.local/share/drop/envs/<id>/etc overlay layer, its files override /etc files
~	~/.local/share/drop/envs/<id>/home	read-write, persistent across runs; the real user home dir and /var are hidden
/var	~/.local/share/drop/envs/<id>/var
/tmp	/tmp/drop-$USER/tmp/<id><suffix>	read-write, persistent, subject to the host's policy for cleaning /tmp
/proc /sys /run /dev	-	created fresh
/dev/null /dev/zero /dev/full /dev/random /dev/urandom	/dev/null /dev/zero /dev/full /dev/random /dev/urandom	read-write