Where's the GUI administration tool?
The Firebird project provides the server and command-line client tools. It also provides various drivers for connectivity (JDBC, ODBC, C, etc.). The project doesn't have its own GUI tool as IBConsole was not open sourced by Borland.
There is a related open source FlameRobin project that aims to create a GUI tool available on all platforms Firebird supports. At the current stage of development it is quite usable, and supports most of the needed day-to-day features like backup, restore, running queries, browsing database structure, extracting metadata, granting privileges, etc.
There are other open source and commercial projects available. Here's a list: