You are a genius!!! Thank you very much! I'm staying with Firefox 52 ESR because my Scrapbook didn't work with Quantum.
I installed ScrapBee on Windows7. I had Scrapbook Plus.

Some things to fix:
1) I had a little problem with the installation:
First, you have to launch the install.bat in a prompt administrator, otherwise you got "Access denied" error when it tries to wirte in the registry;

2) Then, in the batch file I changed the two lines as:
reg add "HKEY_CURRENT_USER\Software\Mozilla\NativeMessagingHosts\scrapbee_backend" /d %USERPROFILE%\Downloads\scrapbee\scrapbee_backend.json /f
reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\NativeMessagingHosts\scrapbee_backend" /d %USERPROFILE%\Downloads\scrapbee\scrapbee_backend.json /f

I changed the command %cd%\
with
%USERPROFILE%\Downloads
because %cd% pointed to my System32 folder, instead of Downloads folder (because I run the batch file with System32's cmd.exe).

3) All my old elements in the original rdf file with a type as "NS18:type="combine" (more pages in one), or
"NS18:type="site"
don't work, but if I empty the tag with a empty string
for ex.: "combine" --> "" in the scrapbook.rdf file, I can load the pages.

That's all for the moment. If I'll find others glitches, I write them to you.
Thanks again. I can install the new Firefox version, now! :-)

Awesome!!! Looks like a good old Scrapbook. And it works. I'm looking forward for pulling my 50 Gb scrapbook from backup and testing it.
1. Have you any plans for adding search feature?
2. Would you be so kind as to give me a link of backend source code?
UPD: Found backend source inside extension package. I assume you've left third party site links in refer and host request headers just due to negligence :)