Multiple dependencies bundled in one file (previously "bundles" config option)

[MBelniak]

• SystemJS Version:
• Which library are you using?
  • system.js
  • s.js
  • system-node.cjs
• Which extras are you using?
  • AMD extra
  • Named Exports
  • Named Register
  • Transform
  • Use Default
  • Global
  • Dynamic Import Maps
• Are you using any custom hooks?

Question

What happened to "bundles" option that I keep seeing in old posts with version 0.x? As I understand, it allowed bundling multiple dependencies in one file and then use one http request to fetch multiple dependencies. Is it disallowed right now because of "one file - one module" idea? I see some clues indicating this idea in #2092 (comment)
IMO it would be beneficial if I could fetch 20 libraries within 4 API calls, especially in microfrontends architecture where I could end up having 50 various shared components. Neither doing 50 requests nor bundling the components is optimal. I know RequireJS has "bundles" option which works really nice, even with webpack where you only really need webpack-concat-plugin.