What does "Endstops Z" mean?

Background:
Anet A8 (lots of custom upgrades, yadda yadda.
Marlin 1.1.8

I am seeing"Endstops Z" printed at the bottom of the LCD display lately. I haven't a clue what that means. I am SURE that this has come up here before, unfortunately, the search engine and I do not see eye-to-eye and I can't find a thread with that topic name.
So, I guess that I'll try to see if someone can refer me, or has the quick explation about someting obvious that I am missing.
So,
What the heck does this mean?

Thanks,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

That your Z endstop is triggered.

Quote
Dust
That your Z endstop is triggered.

So this is a warning that it got triggered during a print?

Hmm, that is problematic. It would mean that my switch has developed some kind of hysteresis that it did not have previously. That could compromise the bed zero point, especially if it triggered too high at just the wrong time. Time to troubleshoot the endstop setup.

Thanks,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.