Drupal 8.x

There is already a docs page about this:
https://www.drupal.org/docs/testing/phpunit-in-drupal/running-phpunit-tests

I've tried to follow that, including creating a browser_output directory and setting up the configuration file (phpunit.xml).

But #2 in the instructions is a stumbling block. It says:

I made a module for Drupal 8.9

https://git.drupalcode.org/sandbox/zenimagine-3076032/-/tree/master

On my /user/ID/tasks page I have this error :

Should my git repo be in my_project_dir or my_project_dir/web?

We use paragraphs "insert block as paragraph" to insert blocks into pages.

Recently we have become unable to create or update any "insert block and paragraph" instances. (although existing instances of them still display the correct content on the front end pages)

We are able to create and update instances of other types of paragraph. We are able to place blocks in template regions.

Whenever we try to edit and instance of "insert block as paragraph" a spinning loading icon appears and then nothing happens.

Dear people,
 

Is it possible to have an installation of drupal with two domainnames pointing to the same drupal installation?

drupal8.devel.org 
domainname.com

I tried, but drupal wants to make a new installation.

settings.php is in folder: devel.org/drupal8/sites/drupal8 ,but I get the same result using folder: devel.org/drupal8/sites/default

folder structure

-devel.org
-- devel.org/www
-- devel.org/drupal7
-- devel.org/drupal8
-- devel.org/drupal8/sites/default
-- devel.org/drupal8/sites/drupal8