> Who is "we"?

$dayjob; does it really matter who as long as it's an example of it being useful to someone?

> putting types in a totally separate file is an abysmal UX.

Is it though? I much prefer

   def frobz(fizbazbang)
     # ... the code

to

   def frobz(Hash<Symbol | String | Integer, Array<String | Integer>> fizbazbang) -> Array<Hash<String | Integer, String>> fizbazbang
     # ... the code

It's the job of the code editor to get that information surfaced to me at the proper place (e.g virtual content like vim inlay hints, hover tooltips, those vscode embeds or whatever they are called). If I need to jump quickly I have projections† set up.

Having the types inline isn't that useful anyway as it gives yo only the signature but gives you no info of whatever type intermediate things are without much thinking.

And interesting things happen when you have separate `.rbs` files: I started to develop some things type first then progressively fill the implementation in.

† Well known because of https://github.com/tpope/vim-projectionist but projections are not limited to vim.