When you have a `captures` object it allows you to assign the scope based upon the index into one of the matched group of the `match` pattern.

So your diff is saying "Assign a scope of `variable.ordered.list.gfm` to the text matched from group 1 of the pattern  `^\\s*\\d*\\.[ \\t]+`".  Your pattern was just missing the parens needed to have a group 1.