Is the .htaccess file modified?

The only case in which the .htaccess file is modified is if the plugin detects that your site is installed in a subdirectory.

For example, if your core site URL appears to be something like "https://your-domain.com/wordpress/", then the following code is added to the .htaccess file:

# BEGIN DMS plugin

RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{HTTP_HOST} !^' . $base_host . '
RewriteRule . /index.php [L]

END DMS plugin