I think the answer can be found at The pkgver() function

To use pkgver(), you still need to declare the pkgver variable with the most recent value. makepkg will invoke function pkgver(), and update variable pkgver accordingly.

I read that as set pkgver to the most recent version at the time you last updated the PKGBUILD. Then the pkgver() function will update it when building the package. I guess you just need something set. It's not clear to me if it actually matters or not.

Love it!

Yes, it took a little digging to find it! Not sure why it's necessary if it's unused. Maybe for error checking? Is it tricky for shell scripts to detect whether a function (i.e. pkgver()) has been defined?

What fun! I like this idea. You should add some screenshots.

What about spawning once and for all? It would hide on startup. Then keypress shows it and starts the timer to rehide it. Then you wouldn't have to worry about process management with flock. Each keypress just sets it to visible (which is fine if.it's already visible) and restarts the timer.

You could use your daemon manager (systemd most commonly) to manage the process.

Just a thought. In any event, looks quite cool and I'll give it a try 😃