$ ./scripts/dbgrbyd.py disk 4096 0 -t
mdir 0x0, rev 1, size 121
off tag data (truncated)
0000005e: +-+-+--> uattr 0x01 4 aa aa aa aa ....
0000000f: | | '--> uattr 0x02 4 aa aa aa aa ....
0000001d: | '----> uattr 0x03 4 aa aa aa aa ....
0000002d: | .----> uattr 0x04 4 aa aa aa aa ....
0000003d: | | .--> uattr 0x05 4 aa aa aa aa ....
0000004f: '-+-+-+> uattr 0x06 4 aa aa aa aa ....
00000004: '> uattr 0x07 4 aa aa aa aa ....
Unfortunately this tree can end up a bit confusing when alt pointers
live in unrelated search paths...