FakeFullScreen
FakeFullScreen is a flag that allows a window to go into fullscreen in windowed
mode.
The flag can be set via client rules and if set it means that when a window goes into fullscreen mode then it will do so within the respective tiled area that is allocated to it.
Tip: you can combine the FakeFullScreen and FullScreen flags in a client rule
to have it start in fake fullscreen mode, as seen above.
Also refer to the togglefakefullscreen function.
In firefox it is possible to go to about:config where one can set full-screen-api:ignore-widgets
to true to constrain fullscreen to the tile. This allows for firefox to go into fullscreen within
the tiled constraints (a.k.a. fake fullscreen) in a window manager independent way.
In Chromium based browsers the --app command line flag works in a similar manner, e.g.
chromium --app="https://example.org"