Message output when downloading a file

I am new to using NextCloud. Recently, I installed Nextcloud 18.0.2. And added some local external storage.

In Nextcloud, I noticed a feature that if you left-click on a file, it starts to download. I need to configure Nextcloud so that when a user tries to download a file (with one click of the left button) a message pops up asking him to wait a few minutes.

I can’t find the code that describes the action of clicking on a file. I will be glad to any advice.