I'm not as familiar with the formats as you are, all I meant was - with the assumption that the CQ viewer is doing the same, with {stdFormat} as intermediary - surely any other viewer could be used.

Just as long as it 'hot reloads', and then you can configure editor/IDE to compile the {stdFormat} file on save.

No need for the viewer to be first-party (to the language). (If assumption valid.)