Essense is IDA Pro plugin. It's main purpose is to save essense of IDA database to XML-storage. It's like 'Dump database to IDC' IDA command, but with some difference: essense is function-based (by default, plugin will save only user-modified functions). Next, plugin is like IDA signatures - try to save only 'valuable' instruction length, so essense is become position and file independent.
This can be useful, if you analysed some version of file and now try to load newer version. Or you analyse several files, which use same library/API. You can just save selected function from current database to XML-file (essense) and then just find and load them in new database.You will load almost everything:
* Structures used in this function
* Enums used in this function
* Frame of function
* Names, comments, etc...
