Remote System Explorer is result of Eclipse Target Management team work. It support SSH, Telnet, FTP and DStore protocols.
The purpose of the entry is to let install it with one drag-and-drop by using Install button.
Example of such usage is Nodeclipse Plugins List
You can find the homepage here: https://www.eclipse.org/tm/
The install/update url is (as I post this) http://download.eclipse.org/tm/updates/4.5.0/repository/
However you should check the downloads page from the project page.