What is the X7 in the Destroyer?

    • What is the X7 in the Destroyer?

      I don´t know why I saw it today... but what´s the meaning of "X7" in the Destroyer on the Login Page?

      Started to google a little bit, and only find one thread asking the same but with no answer on the US Board. So, I started to search by images. And it looks like only the Destroyer has that X7 on it and Cruiser has "21". The rest of the ships are blank.
      Another curious thing is that some destroyers got it and some other do not ?(

      Let´s see examples:

      OGame 15th anniversary by @-pili 02 Oct 2017


      Wreck field- new feature by @Valent Jan 29th 2016 at a simple gaze, there is nothing. Zoom it and you can see a burred "X" but what's next is not a "7" Still, it is in a different position compared to the first picture


      So what does X7 mean? Is there different kind of Destroyer or different codes? Alien ships do not have X7 :P ?

      When did this start? For old-school players, you know this was not the original picture of the Destroyer, this one was...

      And you can see there is nothing there... but look at this concept one of the "new" (actual) model

      The "X7" is clearly there and must have a meaning. Maybe a sort of ID for the ship as many countries do with their no spaceships of course.