Ubuntu's Yaru theme has adopted a change to change all button, slider, widget, and toggle elements to orange instead of eggplant. A similar replacement is made in the set of icons. Changed the color of the active window close button from orange to gray, and the color of slider handles from light gray to white. If the change is not reverted, an updated color scheme will be offered in the Ubuntu 22.04 release.
As a motive for changing colors, the limitations of the libadwaita library are noted, which, starting with GTK 4.4, includes components of the Adwaita theme used in GNOME. This library does not allow more than one accent color and applies a gray color to the window close button in order to achieve uniform title elements.
Source: opennet.ru