How do I call legacy PHP files? I am unable to call PHP files inside the Drupal directory. My task is maintaining staff's old pages on the new platform. With pages written on clear HTML, there is no problem: I place files in a folder I created (domain.org/sites/default/files/share/staff_folder).

In sites/default/files/.htaccess I added DirectoryIndex share and now the link to the domain.org/sites/default/files/share/staff_folder/index.html can be used. When I import pages written in PHP, e.g. calling domain.org/sites/default/files/share/staff2_folder/index.php, I get a 403 error:


  Forbidden
  
  You don't have permission to access /sites/default/files/share/staff2_folder/index.php on this server.


While /sites/default/files/share/staff2_folder/index.html still works.
This is the part of .htaccess, which controls the access to php files:

  # For security reasons, deny access to other PHP files on public sites.
  # Note: The following URI conditions are not anchored at the start (^),
  # because Drupal may be located in a subdirectory. To further improve
  # security, you can replace '!/' with '!^/'.
  # Allow access to PHP files in /core (like authorize.php or install.php):
  RewriteCond %{REQUEST_URI} !/core/[^/]*\.php$
  # Allow access to test-specific PHP files:
  RewriteCond %{REQUEST_URI} !/core/modules/system/tests/https?.php
  # Allow access to Statistics module's custom front controller.
  # Copy and adapt this rule to directly execute PHP files in contributed or
  # custom modules or to run another PHP application in the same directory.
  RewriteCond %{REQUEST_URI} !/core/modules/statistics/statistics.php$
  # Deny access to any other PHP files that do not match the rules above.
  # Specifically, disallow autoload.php from being served directly.
  RewriteRule "^(.+/.*|autoload)\.php($|/)" - [F]


You can see, how the access for statistics.php is allowed. You can add your own rules (at your own risk).