This is not the first change Microsoft has made to the History hub. Last month, the company extended the length of the History hub to accommodate more browsing history, allowing users to view a larger portion of their browsing activity at once.
Microsoft has been actively working on refining the interface of Edge overall. One recent addition is a darker dark mode, which features a fully black interface instead of a dark gray one. However, this change is also in the Canary channel, meaning it is still in the testing phase.