The fix for the dependency is that the entry is incorrect. Though it still does not work for me after this change.

In the HideGroupFrames.txt the entry for "DependsOn" should be:

And not:

Edit:
This may or may not function with this fix. I removed it and then later found I had a conflict with another addon that was toggling the group frame back visible. I used a program called DocFetcher to search for all instances of "ZO_UnitFramesGroups" in my addon folder.

Well much to your chagrin but I already had LibAddonMenu-2.0 installed.

It tells you what you need to do there right below "Required addons"? Check the dependencies! It's missing LibAddonMenu-2.0.
Dependencies mean: If not there, the addon cannot load nor work! So download them just like normal addons.

I already wrote that to your forum post: You need to install LibAddonMenu to your live/AddOns folder once properly (as many addons need this library).

Thank you for taking the time to try to make this, unfortunately no dice.

Here is a fixed version, also fixing the SavedVariables to be server dependent and work properly without definign a SV table and then not using it...

Hide Group Frames v1.1 fixed by Baertram

A general "How to fix addons with libs subfolder" which break the other addon settings can be found here, so you can do that on your own for the next addon where you find that:
https://www.esoui.com/forums/showthread.php?t=9149
Read below "subfolder libs" and "LibStub removal"

This does work when you enable the setting under Settings > Addons > Hide Group Frames.

However this will HIDE all other addons for some reason until you disable this addon and reload ui.

Fix?

fr

Very interesting addon. Is it possible to implement a key bind to hide and display group frames?