What command would you use to display block and superblock group information?

The command that provides detailed information about ext2, ext3, and ext4 file systems, including block and superblock group information, is indeed "dumpe2fs." This utility reads the file system superblocks and displays information about the filesystem's layout, including the block size, the number of inodes, and the allocation groups. It is commonly used for troubleshooting and analyzing file systems.

The other options, while related to file system management in Linux, do not specifically focus on providing detailed superblock and block group information. "fsck" is a tool used to check and optionally repair a Linux filesystem, primarily ensuring data integrity rather than displaying layout information. "rune2fs" is not a standard command; it appears to be a misreference. “mdadm” is used for managing Linux software RAID arrays, which relates to storage management but does not deal with filesystem specifics like superblock or block group information. Thus, "dumpe2fs" stands out as the specific tool for this purpose.