WordPress Drop-In Plugin Feature Function Information

Hi, can anyone give me some information?

So I have 2 domains, domain 1 in the plug-in menu does not show a drop-in while domain 1 again in the plugin menu appears a drop-in with 1 item, namely advanced-cache.php, more clearly can see the picture from this link:

https://kevdees.com/what-are-wordpress-drop-in-plugins/#:~:text=WordPress%20drop%2Din%20plugins%20are,developers%20or%20other%20regular%20plugins.&text=For%20example%2C%20you%20can%20use,file%20and%20it’s%20wpdb%20class.

I’ve read the article on the link but don’t understand the function of the wordpress drop-in plugin feature for what and why it can appear while the domain 1 again doesn’t appear.

Next, how to bring up and remove these features?

thanks!

• This topic was modified 4 years, 8 months ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not a Requests and Feedback topic