Why so little code comment in Discourse Codebase? (Github)

Development
4

I hope you guys(Discourse core team) can write few post about the
big picture view on Discourse codebase..
(not like “why chose Ember.js” I already read that one. deeper than that)

like:

  1. Why this folder structure(Ruby on Rails & Ember.js put together)
    I guess if you guys make Discourse from scratch in 2018,
    would decide separated Rails&Ember into 2 repo?
    or different folder structure

  2. What’s the different between GlobalSetting & SiteSetting?

  3. What’s the core model of Discourse? (Users&Post&Topic)?

  4. why preload_script is needed? example <%= preload_script 'break_string' %>
    preload_script return

# ... some other code
<link rel='preload' href='#{path}' as='script'/>
<script src='#{path}'></script>".html_safe

so it’s for SEO or some other reason?

  1. and few other question I couldn’t recall right now