mkcard.txt and ext4



I followed the instructions from here:

where it's written:
Format the SD card using mkcard.txt. For example: sh mkcard.txt
/dev/sdX, where X is the drive letter of the SD card. On systems like
Ubuntu that would look like 'sudo sh mkcard.txt /dev/sdX'.
This assumes that the SD card has the root filesystem (ext4) partition
mounted as /media/rootfs.

The question:
how is it possible to be ext4 if apparently the command from mkcard.txt:
mke2fs -j -L "Angstrom" ${PARTITION2}
creates ext3 partition.

Who's wrong?