Hi - the vera UI displays string literals. I selected a format that was at least (partially) sensitive to international variations (i.e. did not assume all formats were European of American) and was reasonably compact in terms of line length.
It’s not anything related to google - just a lazy design decision I made
To be honest - I had not thought about allowing the user to define the date and time layout. I’ll take a look as soon as I can (I’m very busy for the next few days) and see if it’s easy to do without having to change the code too much.
The default used by GCal is %H:%M %b %d
Note when editing the variable that quotes are not needed. You can revert back to the default by entering two double quotes “”. Note that after each change to this variable - you will need to reboot the vera for the change to take effect.