yes it is solved

sorry my mistake, now I understand the "d" is past tense meaning "status," whereas if it said Enable not "Enabled", that would be present tense meaning "to be done". I over generalized my experience with video buttons and wasted a lot of time. Thanks you Dave R and TIG my apologizes

thanks TIG I agree it is confusing -- I thought I was getting exact by naming the menu where LibFredo6 was to be found, but instead it is confusing in terms of the OS -- thanks very much for your help

I am so sorry to have wasted your time. It appears that I make a bad assumption.

when you play a video on youtube, you click on the triangle to play the video and the triangle is replaced to two parallel lines. when you want to pause the video you click on the pause button and it is replaced with the triangle.

I assumed this was true with Extension Manage -- if you want to enable an extension you clicked on Enabled and button switched to Disabled so that you could click on that button to disable the extension. It appears that the "d" makes all the difference. The button shows the status of the extension "Enabled" and clicking on it does the opposite, so I was clicking on "Enabled" thinking I was enabling the extension, whereas I was disabling it. All the difference in a "d" thanks for the help, sorry to have trouble you so

thanks so much TIG but my PC died -- I am working on my MacBook Pro
I don't have access to those file on the Mac, or better yet I don't know how to get to them, I tried going to "Library" but I could not find anything related to SU but there were a lot of folders and did not go thru them all

I went to Applications folder in Finder, moved the SU folder to the Trash, emptied the trash, rebooted the SU dmg reinstalled SU and to my surprise the Extension Manager was as I had left it with all the extension that I have loaded still there, but unfortunately LibFredo6 Settings still did not show up under the Window menu

To answer Dave R's question -- install LibFredo6 by clicking on the "Install Extension" button in Extension Manager, selecting the file and clicking on "Open", the file showed up in the Extension Manager I clicked on Enable, quit SU, restarted SU and still no LibFredo6 Settings under the Window menu

uninstalling SU, didn't seem to clear the Extension Manager -- how would I do that???

yes I downloaded three files from Fredo --
LibFredo6_v9.1b.rbz
Curvizard_v2.4a.rbz
Curviloft_v1.8a.rbz

yes I installed all three file via Extension Manager, enabled all three, yet there is NO "LibFredo6 Settings" anywhere under any of the menu or submenus

yes I have restarted SU many times,
yes I have restarted my computer several times

yet there is no "LibFredo6 Settings" under any of the menus

Fredo worked in my PC "rest in peace" but it will not work in my MacBook Pro

i know that "libfredo is a supporting (required) library for Fredo's extensions and not an extension in itself" it states that on its website. Knowing that does not solve my problem -- Fredo does not show up in the Window menu or anywhere else.

"Each of these Fredo tools comes in its own RBZ, each of which need to be installed individually" yes I have downloaded them and installed them and enabled them and they show up in Extension Manager, yet they do not show up under any of the menus in SU

"Note that LibFredo6 must always remain active.
Its setting can be accessed [if needed] from the Window submenu "LibFredo6 Settings..."
When active each of Fredo's tools get entries in the Tools submenu items "Fredo Collection" and "Fredo Tools"..." I have restarted SU many times, I have restart the computer several times, yet "LibFredo6 Settings" does not show up under the Window submenu or anywhere else. They did on my PC, but the HD on my PC bit of dust and it will be another ten days before I get another Dell shipped to me, so I thought I might get some work done on my MacBook Pro
but LibFridoSettings do NOT show up under any menu so I can not access them the other tools. I have installed another extensions and they work. It is just this one tool that I need that does not show up.

MacBook Pro mac OS 10.14.6 Mojave
SketchUp Make 2017

downloaded LibFredo6_v9.1b.rbz
install file via Extension Manager
enabled file

did not find libFredo6 under Window menu
quit SketchUp
restarted SketchUp

still no libFredo6
research the internet
rebooted the computer
restarted SketchUp

still no libFredo6
load other plugins from Fredo
they all show up in Extension Manager
but they do not show up in or under any of the menus in SketchUp
four hours later, other extensions will load but not Fredo products -- any ideas