cd any

for f in *.zst *.xz; do
    [[ -e "$f" ]] || continue
    [[ -e "$f.sig" ]] || echo "SIG fehlt: $f.sig"
done

for f in *.zst.sig *.xz.sig; do
    [[ -e "$f" ]] || continue
    base="${f%.sig}"
    [[ -e "$base" ]] || echo "ZST fehlt: $base"
done