This was a deliberate change by upstream as a part of adding support for subordinate ids. You can find the full list of patches in shadow devel mailing list:
https://lists.alioth.debian.org/pipermail/pkg-shadow-devel/2013-January/thread.html#9561
The specific patch affecting userdel can be found here:
https://lists.alioth.debian.org/pipermail/pkg-shadow-devel/2013-January/009561.html
This was a deliberate change by upstream as a part of adding support for subordinate ids. You can find the full list of patches in shadow devel mailing list:
https:/ /lists. alioth. debian. org/pipermail/ pkg-shadow- devel/2013- January/ thread. html#9561
The specific patch affecting userdel can be found here:
https:/ /lists. alioth. debian. org/pipermail/ pkg-shadow- devel/2013- January/ 009561. html