Not sure what you mean by »app« here … But let me explain. I have a hosted/managed Nextcloud Instance on »domaina.com« and and would like to create a website for »domainb.com«. The website shall pull some files from the nextcloud instance, so the browser i going to make an OPTIONS request to »domaina.com«.
Since I cannot modify the webserver setup, I am searching for a way to add those CORS Routes (http OPTION) and needed headers, such that the website from »domainb.com« finally may pull the data.
Using your glossary here, I think the website is what you refer to as app.
THANKS a lot for your help!