Eou-tmg-(undub)-decrtd-ziperto.rar < Top 50 Complete >

This indicates the ROM has been modified to include the original Japanese voice acting while retaining English text. This is highly desired by fans who prefer the original audio over dubbed versions.

Based on the file naming convention, refers to a specific, modified ROM file for the Nintendo 3DS game Etrian Odyssey Untold: The Millennium Girl . EOU-TMG-(UNDUB)-DecrTD-Ziperto.rar

These types of files are used to experience the "definitive" version of the game, combining the best aspects of both localization and original audio, playable on alternative platforms. This indicates the ROM has been modified to

If you're asking about this for technical or archival reasons, I can also explain: How to What the differences are between this and the original Where to find other similar modified ROMs These types of files are used to experience

Here is an informative breakdown of what this file represents:

A .rar file is a compressed archive containing the .3ds or .cia game file.