src/jdk.jpackage/linux/classes/jdk/jpackage/internal/LinuxDebBundler.java

*** 405,414 ****
--- 405,427 ----
              IOUtils.exec(pb, false, ps);
              return baos.toString().split("\n", 2)[0];
          }
      }
  
+     public static boolean isDebian() {
+         // we are just going to run "dpkg -s coreutils" ans assume Debian
+         // or deritive if no error is returned.
+         var pb = new ProcessBuilder(TOOL_DPKG, "-s", "coreutils");
+         try {
+             int ret = pb.start().waitFor();
+             return (ret == 0);
+         } catch (IOException | InterruptedException e) {
+             // just fall thru
+         }
+         return false;
+     }
+ 
      private long getInstalledSizeKB(Map<String, ? super Object> params) {
          return getInstalledSizeKB(APP_IMAGE_ROOT.fetchFrom(params)) >> 10;
      }
  
      private long getInstalledSizeKB(File dir) {
*** 937,942 ****
--- 950,961 ----
          } catch (Exception e) {
              Log.verbose(e);
              return 0;
          }
      }
+ 
+     @Override
+     public boolean isDefault() {
+         return isDebian();
+     }
+ 
  }