That is the button behind the “emergency reset hole” in the bottom case panel. It’s explained in the user manual.
Emergency Reset Hole
Gotta be a punk rock band name, no?
If you do have the smart PSU and power management server you probably also went down the rabbit hole of scripting the power cycling, right? Maybe made that server hardened against power loss disk corruption so it can be run until UPS battery exhaustion.
What if there is a power outage and NUT shuts everything down? Would be nice to have everything brought back up in an orderly way when power returns. Without manual intervention. But keeping you informed via logging and push notifications.
Here is a similar thing in audio monologue:

There are a lot. I have a long playlist called “mope” But the first song that came to mind is:
“Blue Valentine” by Tom Waits. youtu.be/wsw0aWXufqM

It seems to me that the preposition usage corresponds to the boarding language pretty closely. Where “on” sounds most natural is also where “boarding” seems most appropriate.
Here is one linguist’s take, with proposed usage cases at the end: itre.cis.upenn.edu/~myl/…/005224.html
The schedule/route condition makes a lot of sense to me. Consider a bus converted to personal use as an rv:
“I boarded my bus and drove to the mountains” is a valid English sentence, but it sounds odd to me. But if it’s still a regular bus and drove->rode it works.
“I drove to the mountains in my bus” sounds better. Same vehicle as a city/school bus, different context. Change to a regular bus and drove->rode doesn’t sound right without also changing “in my” to “on the”.
Funny, that’s exactly how I used to do it. And I still do if I want cool eggs sooner.
Our eggs may be different (US here, working from refrigerated washed eggs) or I am less lucky. I had mostly success, but sometimes had troublesome eggs and would have a few mangy looking ones where the white sticks to the inside of the shell and water doesn’t change it. Chunks of white pull away. After switching to the Kenji method I have more success than before. Still once in a while I get a stuck shell, but less often.