`.I` (n'th permutation builtin) doesn't work on strings

[kcruijss]

Although .I isn't too useful for code-golfing, since œ + è is basically the same (although it depends on the stack order I guess), .I is A LOT faster and therefore pretty useful sometimes. Unfortunately, it only works with lists, and for strings you'll basically have to add a leading S and trailing J.

Try it online
Found in this 05AB1E answer of mine.