Coming two months after KDE Plasma 6.6.5, the KDE Plasma 6.6.6 release is a bugfix one that addresses numerous issues, including a clipboard-related issue that could make XWayland-using apps lag or freeze after locking the screen.
KDE Plasma 6.6.6 also fixes a KWin crash that occurred when some apps opened dialogs and pop-ups in non-standard ways, a regression in the icon displayed by the Networks widget for VLAN networks, and a Qt regression that caused job progress notifications to remain visible on screen until explicitly dismissed.