404 – feature request to include an option to save a custom 404 page

I have a custom 404 page on my site. I’d like to request an option to force create a static version of the 404 page.

Placing the 404.html into the additional URLs or additional files section does not work since any address that returns a 404 is not stored.

In my case, I created a copy called 404-2 and then manually changed the file name for my live site.