The file contents are as follows:
#REWRITE-START
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.tld [NC]
RewriteRule ^(.*) https://subdomain.example.tld [L,R=302]
</IfModule>
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www.example.tld [NC]
RewriteRule ^(.*) https://subdomain.example.tld [L,R=302]
</IfModule>
#REWRITE-END
The redirect rule was added using the form created from pressing the button labeled "Add redirection".
aaPanel_Kern