Any required callbacks to WP.com or WP.org?

by

It is a little hard to quickly audit WP code base for wordpress.org links, because they are extensively used in inline documentation. On top of my head the main (if not only) requests are probably to api.wordpress.org for updates.

For resources WP generally only uses bundled assets. The two notable exceptions are:

  1. Deprecated libraries (such as prototype), which aren’t used in core anymore. They are registered to load from ajax.googleapis.com and no longer bundled.
  2. Web fonts in admin which aren’t bundled because of technical challenges. They are registered to load from fonts.googleapis.com.