How to deal with non-standard joomla configuration?

Question

Joomla

I inherited a site on joomla.
2 unexpected problems:
1) The administrator folder is missing, and mysite.ru/administrator won't open either. Apparently, the previous programmer reconfigured access to the admin panel, how to understand where?
2) There is no file in the root configuration.php at the root, where could it be hidden? (I ran it through the search - I didn’t find it)
PS Maybe this is a fork of Joomla or plugins turned everything upside down?
At first I doubted that it was joomla, but Wappalyzer says so.
I'm inclined to believe him, here's a piece from the head, along the way it looks like

<link href="/templates/shape5_vertex/favicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />
  <link rel="stylesheet" href="/cache/widgetkit/widgetkit-22c02114.css" type="text/css" />
  <link rel="stylesheet" href="/plugins/system/mediabox_ck/mediabox_ck/mediaboxAdvBlack21.css" type="text/css" />
  <link rel="stylesheet" href="/templates/shape5_vertex/css/s5_flex_menu.css" type="text/css" />
  <link rel="stylesheet" href="/modules/mod_slideshowck/themes/default/css/camera.css" type="text/css" />
  <link rel="stylesheet" href="/media/com_finder/css/finder.css" type="text/css" />

Tellingly, all sorts of definitions like 2ip.ru do not find any signs of CMS.
The correctness of the path to ftp was specially checked, filled in the test file test.html with the text 123 - the norms are displayed.

Answer 1

It really turned out to be not joomla, but some kind of self-writing, the authors of which mowed down under Joomla. It's just that some paths were similar, which was misleading.

Answer 2

Are you sure it's joomla? All plugins hide paths when requested, but do not change the folder or file structure. This is a change in the architecture of the CMS, it would be necessary to do all the manipulations anew with each update of joomla ...
Drop the site, let's see.

Answer 3

May have been removed from www/docroot above for safety.