Did the bootstrap process change? I've had minimal experience with Drupal 7, and I am migrating over to Drupal 8. 

I was curious as to what the flow of execution is when serving up a basic page in Drupal 8. In Drupal 7, this was considered the bootstrap process.

Is there an equivalent in Drupal 8?
The process is rather different. There are some common elements but maybe what can get confusing is how D8 leverages the Symfony Framework.

use Drupal\Core\DrupalKernel;
use Symfony\Component\HttpFoundation\Request;

$autoloader = require_once 'autoload.php';

$kernel = new DrupalKernel('prod', $autoloader);

$request = Request::createFromGlobals();
$response = $kernel-&gt;handle($request);
$response-&gt;send();

$kernel-&gt;terminate($request, $response);


As can be witnessed by the index.php, things look a bit different. But it is essentially "bootstrapping" functionality. To get a really good sense of what is going on, I would highly recommend reading the following:

https://cipix.nl/understanding-drupal-8-part-1-general-structure-framework

Also, the Drupal 8 Documentation helps to get a good grasp on what is available to work with:

https://www.drupal.org/docs/8/

Especially giving the API's a good looksy:

https://www.drupal.org/docs/8/api

As I said, it's quite different than before. A lot more OOP going on. It's quite powerful and gives developers a lot more tools to work with but if you aren't used to how PSR-0 and PSR-4 autoloading work, you might find it hard to debug and grock. 

Good luck and Happy Drupalling!