> " IIUC you're implementing comma-separated lists {abc,def} and nested braces {a{b,c}d,efg} but not ranges {a..z}."

Exactly.

Although that's just because at the time I sent the patch, I didn't know about ranges in shells.

So I just implemented the part of curly brace expansion that I knew of and felt would be useful.

If ranges are an expected feature from shells, then it would probably be a worthwhile addition.