The kernel team is working on final integration for kernel 5.1.
This version was just recently released, and will arrive soon in Fedora. This version has many security fixes included.
As a result, the Fedora kernel and QA teams have organized a test week from Monday, May 13, 2019 through Saturday, May 18, 2019.
Read the full article on the Fedora Magazine.
What is a test day? Read more on the wiki page.