For a more indepth article about the menu functions, please see; Debug Menu.
A meta-location included in Shadow Hearts: Covenant that is not available during the normal gameplay and can be reached only by using a cheat device (there are two known methods/codes to accomplish this).
It's present in all versions of the game. The area consists of a square floor floating in space and a save point.
By pressing the action button, the player can access an extensive menu system that allows for modifying game flags, warping to any location in the game, unlocking every item (including dummied out items), modifying party members data (their stats, names) etc. The menus are mostly in Japanese and many options cause the game to crash if not used correctly.
Attempting to save the game while being in this location also crashes the game, however it's presence strongly suggests that it may be possible to force it as a current location by hacking the game save, which is further supported by the fact that Debug Island appears as a normal location both in the warp and World Map editing menu (it's not on the locations list though). Curiously, the game allows the player to add Sea of Woods to the main locations list, however its name shows up as garbage data and any attempt to enter it (including warping inside) makes the game crash.
The reason for this data existing in the PAL version indicates that it was being considered to include the Director's Cut material as standard. This is not an unusual practice for PAL region games; having a much delayed release date to US and Japanese versions, allowing the developers to make modifications or additions that weren't in the original release.
It would also explain why the Director's Cut only exclusives, (the Meiyuan stud card, Veronica and Lenny's gear, and Yuri's bonus weapon) were translated into English, despite not being accessable otherwise.
The Debug Island was also used in the games sequel, Shadow Hearts: From the New World. However, attempting to access it will crash the game.