am f7a8c0f7: cherrypick Change-Id: Icf0c7772901f742c36ba417e07cc5e299f72849a fix broken links, update the dev guide intro, and update sitemap file

* commit 'f7a8c0f78796ebbeb57381b145c0648d7bc6b84a':
  cherrypick Change-Id: Icf0c7772901f742c36ba417e07cc5e299f72849a fix broken links, update the dev guide intro, and update sitemap file