enhancement
If you want to merge several lists element by element in TL-Script (combine the elements at position n with a function in each case), you have to do this laboriously using an index list. This would be more elegant with the transpose() function:
[[1, 2, 3], ["a", "b", "c"]].transpose(num -> val -> $num + "-" + $val)
results in
["1-a", "2-b", "3-c"]]
If you do not specify a function for merging, you get a list with tuples of the elements at corresponding positions.
If the lists are of different lengths, the shorter lists are implicitly filled with zero.