APFS allocation examples

apfs_allocation.txt

For a 256-block image:   (I see the same for 246-block images)

   1 block for main (current checkpoint's) container superblock
   8 blocks for previous checkpoints and container superblocks
  52 blocks for space manager and related objects
  16 blocks for future expansion?
   6 blocks for allocation info file blocks
------
  83


For a 261,226-block image:

   1 block for main (current checkpoint's) container superblock
  12 blocks for previous checkpoints and container superblocks
 760 blocks for space manager and related objects
  16 blocks for future expansion?
  27 blocks for allocation info file blocks?
------
 816