PMA.studio and PMA.vue preferably are run under the HTTPS-protocol (provided you have an SSL certificate enabled on your webserver).

If you accidentally launch either application under the HTTP protocol instead of the HTTPS protocol, a notification shows during the login procedure.

The notification appears whether you intended to launch the application under HTTP or whether it was an accident. It's up to the end-user to decide whether the message is justified or not (in which can you can continue using the software as is, e.g. when running it on localhost).