diff --git a/spolszczenie_enhanced.tar.gz b/spolszczenie_enhanced.tar.gz
index e855f85..a61823a 100644
Binary files a/spolszczenie_enhanced.tar.gz and b/spolszczenie_enhanced.tar.gz differ
diff --git a/tests/quality_checks.sh b/tests/quality_checks.sh
index d274964..8306d20 100644
--- a/tests/quality_checks.sh
+++ b/tests/quality_checks.sh
@@ -27,11 +27,28 @@ assert_bash_syntax() {
   bash -n "$file" || fail "$file has invalid bash syntax"
 }
 
+assert_archive_clean_for_linux_tar() {
+  local archive="$1"
+  local metadata_entries
+  local xattr_entries
+
+  metadata_entries="$(tar -tzf "$archive" | grep -E '(^|/)\._|(^|/)\.DS_Store$|(^|/)__MACOSX(/|$)' || true)"
+  if [[ -n "$metadata_entries" ]]; then
+    fail "$archive contains macOS metadata files"
+  fi
+
+  xattr_entries="$(gzip -dc "$archive" | strings | grep -E 'LIBARCHIVE\.xattr|SCHILY\.xattr|com\.apple' || true)"
+  if [[ -n "$xattr_entries" ]]; then
+    fail "$archive contains macOS extended attributes"
+  fi
+}
+
 assert_bash_syntax "$ROOT_DIR/dapostinstall.sh"
 assert_bash_syntax "$ROOT_DIR/da_cli.sh"
 assert_bash_syntax "$ROOT_DIR/daupdate.sh"
 
 php -l "$ROOT_DIR/lang_pl.php" >/dev/null || fail "lang_pl.php has invalid PHP syntax"
+assert_archive_clean_for_linux_tar "$ROOT_DIR/spolszczenie_enhanced.tar.gz"
 
 assert_file_contains "$ROOT_DIR/da_cli.sh" '^DEFAULTPACKAGE=NO-LIMIT$'
 assert_file_not_contains "$ROOT_DIR/da_cli.sh" '^eparated list of IP addresses$'