IF YOU HAVE A CUSTOM 404 page, and are getting 404 hits from links without an .html extension,
add this code to the header of the error page (in between the <head> and </head> tags):|
It won't solve all the problems of whatever Yahoo Small Business did in early May, 2019, but it will allow people to get to your pages.
May 20, 2019
This came up from Small Business, but it's not very helpful How can I create my own error pages?