The wt verify -d dump_layout command dumps the layout of a btree for diagnostic purposes. It also includes some extent list information included in the checkpoints in the file. The extents are then grouped by size into buckets and displayed as follows:

extents by bucket: {16KB: 1}, {32KB: 1}, {256KB: 1}, {2MB: 1}, {4MB: 2}

In diagnosing extent list issues it would be helpful to have a complete list of every extent in the extent list, including their offset and size, instead of only grouping them in size buckets. For example:

1:   4096, 552960
2:   561152, 114688
3:   688128, 532480