org-babel-ref-index-list
org-babel-ref-index-list is a compiled Lisp function in `ob-ref.el
'.
(org-babel-ref-index-list INDEX LIS)
Return the subset of LIS indexed by INDEX.
Indices are 0 based and negative indices count from the end of
LIS, so 0 references the first element of LIS and -1 references
the last. If INDEX is separated by ","s then each "portion"
is assumed to index into the next deepest nesting or dimension.
A valid "portion" can consist of either an integer index, two
integers separated by a ":" in which case the entire range is
returned, or an empty string or "*" both of which are
interpreted to mean the entire range and as such are equivalent
to "0:-1".