Why would "/dev/mapper/sddX" will be seen for the "/dev/sddX" device ?

Issue

• Newly added LUNs from SAN are seen at two places, viz. /dev/sddc and /dev/mapper/sddc. There are no udev rules and no multipathing software is installed. Then, under what circumstances /dev/mapper/sddXX names would be seen ?

Jun 12 09:27:03 ins sudo: abs : TTY=pts/1 ; PWD=/home/abs ; USER=root ; COMMAND=/usr/sbin/pvcreate /dev/mapper/sddc1 ; VER=r1-4 ; KINTA=<NONE>
Jun 12 09:27:07 ins sudo: abs : TTY=pts/1 ; PWD=/home/abs ; USER=root ; COMMAND=/usr/sbin/pvcreate /dev/mapper/sddf1 ; VER=r1-4 ; KINTA=<NONE>

PRODVG.vg:description = "Created *before* executing 'vgextend PRDVG /dev/mapper/sddc1'"
PRDVG.vg:description = "Created *before* executing 'vgextend PRDVG /dev/mapper/sddd1'"
PRDVG.vg:description = "Created *before* executing 'vgextend PRDVG /dev/mapper/sdde1'"
PRDVG.vg:description = "Created *before* executing 'vgextend PRDVG /dev/mapper/sddf1'"