Comment # 9 on bug 1209725 from Stefan Hundhammer

Notice how all the thin pool volumes are missing in
storage-inst/06-committed.yml. They are present in the corresponding XML file
06-committed.xml, though; but it's much harder to read because the edges of the
device graph are in the <Holders> sub-hierarachy using SIDs (numeric IDs) as
the reference.

With those SIDs, the thin pool volumes are below LV "thin_pool00":

lvm_lv /dev/system/thin_pool00  sid  93
  lvm_lv /dev/system/var        sid 100
  lvm_lv /dev/system/syslogs    sid 106
  lvm_lv /dev/system/home       sid 112
  lvm_lv /dev/system/opt        sid 118
  lvm_lv /dev/system/extra      sid 124

And this is reflected in <Holders> in 06-committed.xml.