TLDR: Tabbed Windows allows resizable windows to be grouped and easily manipulated, vastly improving UX & Efficiency.

Example: The best demonstration of this feature would be "Groupy" (https://www.stardock.com/products/groupy/) on Windows, where a similar implementation on KDE would be brilliant. Unfortunately, a similar application for KDE does not exist (or for any other WM as far as I can tell).

Feature Proposal:
Windows are able to be grouped, where all windows in the group always have the same position & size. The title bar would be split into tabs, where each tab represents a single window in the group. Clicking on a tab shows and focuses on the selected window (hiding the previously shown window).

Benefits
 - Fast & Easy Window Switching: Instead of slowly searching through a cluttered task bar (default panel) which shows all windows (ie. 'Global Scope'), each group's tab bar only shows the windows in that group (ie. 'local scope'). Instead of fumbling with the task bar: finding the desired app, then finding the desired instance/window of the app; we can instead look to the correct group, then press the correct tab (easily identifying the desired app due to a much lower number of windows in the group compared to all windows in the taskbar)
 - Fast & Easy Window management: By merely resizing/tiling a group, all windows part of the group will automatically inherit the same dimensions/position. Works well with custom tiling.
 - Intuitive: No obscure keyboard shortcuts necessary and the vast majority of people are already familiar with tabs (ie. from web browsers). It would not be crazy to suggest that KDE defaults to: auto-hide task bar (increasing available useful space), tabbed windows on. 



Pls 🥺