So ...

We are going to use a handy plugin called What The File.

Here it is:

https://wordpress.org/plugins/what-the-file/

It's a very small plugin (12 KB), but let's see the usual speed tests ...

Here are my results before installing the plugin ...

... and the result after installing and activating the plugin:

As you can see, the plugin is almost invisible. No more comments needed ...

Now let's see how it works ...