Shrink and move the digital clock to the top of the Open Apps screen as the screen above swipes up out of view

A user-editable SVG clock file in /home/nemo, checked by the Clock program on reboot and on demand (via dbus) could be set up to override the default Clock layout configuration. Examples and templates provided by Jolla would light the way to as many different clocks with tweaked layouts and UI triggers as users want, including switching clock displays by event (e.g. GPS, WLAN) and context.

It sounds like what you ask for is very close to a status bar. While I (and, if you do a forum search, many others) absolutely agree with you, you may want to brace yourself for a flame storm from the self-appointed guardians of the One True Jolla Way.

Meanwhile, I solved the problem by purchasing the OLED TOH (TOHOLED) by Kimmo. Turning the phone around to check the time is much quicker and less inconvenient than the gesture gymnastics one has to do when inside a running app.

The original motivation was for a visually pleasing transition that keeps the clock visible and makes the upper screens clear and distinct from the shift down into the icon-centred interface on the screens beneath, as vertical sliding/swiping/dragging is repeated. That is so at a glance the user knows which current screen level is displaying.