Translations:Tutorials/Using Other Window Managers with Plasma/35/en
Some i3 window rules help you to have notifications and some other plasma windows as floating windows:
for_window [title="Desktop — Plasma"] kill; floating enable; border none for_window [class="plasmashell"] floating enable; for_window [class="Plasma"] floating enable; border none for_window [title="plasma-desktop"] floating enable; border none for_window [title="win7"] floating enable; border none for_window [class="krunner"] floating enable; border none for_window [class="Kmix"] floating enable; border none for_window [class="Klipper"] floating enable; border none for_window [class="Plasmoidviewer"] floating enable; border none for_window [class="(?i)*nextcloud*"] floating disable