The main thing about jcore is that it is written from 0 which should make developer's life easier to understand the coding and extend them. Unfortunately I didn't have the time to add comments to the codes but please don;t hesitate to contact me if you have any questions.
The current jCore has the following features included and implemented:
You build up your site from scrach using blocks (divs) and customizing them with css/js.
Using PHP's implemented translation functionality you can translate any port of the site.
Have multiple menus for e.g. Top Menu, Bottom Menu, Left Menu on your site with unlimited menu items.
Manage your site's content with a WYSIWYG editor and attach files/pictures to them.
Create submit forms with custom fileds and store or send valus trough email.
Extend your site with further functionality like Photogallery or a File sharing module and so on.
jCore uses jQuery for it's front end coding, it even implements it's on jQuery plugins to make implementation of further jQuery plugins easily.
Include posts, modules, blocks, forms and other are of your site in your posts/blocks contents.
Keep your readers up to date with rss feeds.
Easily place ad codes / banners on your site and earn money.
Manage your site members or send out mass emails to let them know about news.
Have your links reendered in a human friendly way so people can remember them easily.
Will protect you from brute force attacks on your user's accounts.
Will protect you from password traders / sharers and notify you of compromised accounts.
Instead of showing a 404 Url Not found page you can customize to show your own text within your own site.
Will let you close your site for maintenance with your own notification text while you are making updates to your site.
Using partial classes you will be able to extend the core features without affecting compatibility for future updates.
These would be the more important features of the jCore but for a real deal you should have a deeper look on things.