Manage pages exist

Hello the image editing tests went well, I realize how simple it is to use, it’s perfect.
Today I have a different problem, I can’t find a pluggin called “Manage Pages”,
Capture du 2021-09-19 15-50-59
the screenshot shows what I’m talking about, this pluggin looks very useful, but I can’t find it in the list of available pluggins, the list is very long, and even by putting in filter “page” or “manage”?
Does this pluggin still exist? Is it really a pluggin, or is it an old page manager? (and in this case I can’t find anything in “available plugins”.
I would like to reach this “manage pages” because according to a tutorial found on Framasoft, I could then modify page elements like, change logo for example.
Thanks for your answers. jef

@jefrey, This very much looks like a very early version of Admin. Would you mind sharing where you found the information about “Manage Pages”