Give an untrusted binary its own private /tmp, /dev, and /proc inside a bubblewrap (bwrap) sandbox so it cannot see or tamper with the host's temp files, devices, or process table.

Documented steps

1. Create a private, size-bounded /tmp: `bwrap --unshare-pid --unshare-user --ro-bind /usr /usr --symlink usr/lib /lib --symlink usr/bin /bin --proc /proc --dev /dev --size 16777216 --tmpfs /tmp --chdir / bash -c 'echo hi > /tmp/x; mount | grep tmp'` — confirms /tmp is a fresh tmpfs bounded by --size rather than the host's real /tmp.
2. Mount a fresh, minimal /dev instead of exposing the host's real devices: `--dev /dev`. Per bwrap.xml (source: https://raw.githubusercontent.com/containers/bubblewrap/main/bwrap.xml), `--dev DEST` mounts a new devtmpfs, which differs from `--dev-bind SRC DEST`, which bind-mounts the host's actual device tree.
3. If one specific host device (e.g. /dev/dri for GPU access) must be exposed, bind it individually: `--dev-bind-try /dev/dri /dev/dri` (per bwrap.xml, `--dev-bind` 'allows device access' and the `-try` variant 'ignores non-existent SRC'); keep this narrowly scoped instead of bind-mounting all of /dev.
4. Mount a private /proc with `--proc /proc`, and combine it with `--unshare-pid` so the sandbox has its own PID namespace and the mounted /proc only exposes processes inside the sandbox.
5. Verify isolation end-to-end: `bwrap --unshare-pid --unshare-user --ro-bind /usr /usr --proc /proc --dev /dev --symlink usr/bin /bin ps aux` and confirm only the sandboxed process tree is visible, not host processes.