Ever since GNOME 3.8 when gnome-shell started to provide the window
switcher functionality itself, the extension has only existed to
change the default behavior of the alt-tab shortcut in the classic
session. Now that we achieve this behavior with a per-desktop override,
there's no longer a need for the extension, so remove it altogether.
Users who prefer the window switcher over the default app switcher
can use the regular keyboard settings to assign a shortcut to the
"Switch windows" action.
https://bugzilla.gnome.org/show_bug.cgi?id=786496