OP moved this question to StackOverflow: https://stackoverflow.com/a/45399792/6471228
Answer via Alex Bauer:
Since the apple-app-site-association file is not a WordPress file, you
have to configure the content type at the server level. This is
different depending on environment (Apache vs. nginx, for example).
This can be hard, if your host doesn’t allow access to low level
configuration.Apache configuration
Modify the
/etc/apache2/sites-available/default-ssl
(or equivalent) file to
include the snippet:
<Directory /path/to/root/directory/> ... <Files
apple-app-site-association> Header set Content-type
"application/pkcs7-mime" </Files> </Directory>nginx configuration
Modify the
/etc/nginx/sites-available/ssl.example.com
(or equivalent)
file to include the location /apple-app-assocation snippet:
server { ... location /apple-app-site-association {
default_type application/pkcs7-mime; } }Source: https://gist.github.com/anhar/6d50c023f442fb2437e1#modifying-the-content-type
In theory I believe it is possible to do the Apache configuration via
a .htaccess file, but I’ve never tried.