The ext2fs translator doesn't support the ext2 format's filetype option.

According to mke2fs(8):

filetype: Store file type information in directory entries.

By setting directory listings' informational d_type field (readdir, etc.), this may avoid the need for subsequent stat calls.

Not all file systems can support this option.

In [hurd]/ext2fs/dir.c the EXT2_FEATURE_INCOMPAT_FILETYPE is generally masked out (is not even considered) when adding a node to a directory in diskfs_direnter_hard and when reading in diskfs_get_directs. The Hurd's ext2fs unconditionally sets this field to 0 (EXT2_FT_UNKNOWN).

e2fsck

Running e2fsck on a file system with the filetype option, will correct the filetype for a lot of files (all EXT2_FT_UNKNOWN?) to either 1 (regular file, EXT2_FT_REG_FILE), or 2 (directory, EXT2_FT_DIR), and likely others. The Hurd's ext2fs will again ignore these fields, of course.