Brace expansions are a shell syntax that lets you perform operations on a series of arguments with variable components without having to type each one out in full. Bash can do a lot with this that Fish can’t, so it’s taken a little work to replicate some common commands in Fish. But not much.
This is a companion discussion topic for the original entry at https://brettterpstra.com/2020/05/08/brace-expansion-and-sequences-in-fish