[rbak-nsp] Explanation of difference between IEUDR and IEUR

[Alex D.]

Hello,
we were running a Smart-Edge 600 with one 10-port Gigabitethernet 
linecards for quite a while. Some days ago, we installed a 2nd card with 
same type.
With "show chassis", i see that it's recognized correctly. Only 
difference i see is in "Initialized Flags"
Can someone give me a short explanation why the first card shows "IEUDR" 
and the other "IEUR".
In command output, i can see the abbreviations, but i would like to know 
what "D-Default Traffic Card" exactly means.
Thanks in advance
Regards
Alex