Extract text from Mozilla and Trainz archives (JA)
To convert JA archives to another format, you need Mozilla Firefox or other Compressed software.
To convert other file formats to the "Application Archive File" file type, you need software like Mozilla Firefox or a similar tool.
The .JA file extension primarily acts as a Mozilla Application Archive. Most commonly encountered as omni.ja, it stores the core interface scripts, layout instructions, and default preferences for browsers like Mozilla Firefox. Alternatively, .JA files are used as Jet Archives in Trainz Simulator to bundle 3D models and textures, or as localized audio packages (Japanese voice lines) managed by Audiokinetic Wwise in games like Cyberpunk 2077.
To open or extract a Mozilla .JA file, users typically rely on standard decompression tools like 7-Zip or WinRAR. This is because Mozilla's implementation is essentially a specialized ZIP file renamed to avoid system conflicts with standard Java Archives (JAR).
Dealing with .JA files is often a frustrating experience. They are highly proprietary containers optimized for fast software loading, not for user editing. If you try to extract, modify, and repack an omni.ja file incorrectly, the browser will instantly crash upon startup. Game-related .JA files present an even bigger challenge; they are closed-source, compiled binary blobs that require niche modding tools or the original game engine to unpack.
Most users look to convert or extract .JA files into standard ZIP folders to access the underlying JS (JavaScript), CSS, TXT, or OGG audio assets. Converting them to a raw archive format allows for modding or inspecting the software's code.
Because these are specialized, application-specific formats, standard online file converters completely fail to process them. If our analysis detects a supported underlying ZIP structure or embedded text, viewing or extraction might still be possible.
Convert.Guru analyzes your JA file, detects the exact format, and lets you read the text inside.
Users also converted GEOPCDX, OVL, MPQ, US, EC and TT files.
If you want to convert JA file to US, EC, TT, CSV, JSON, XML, YAML, YML, TOML, INI, CFG or CONF, you can use Mozilla Firefox or similar software from the "Application Resource Archive" category. In the File menu, look for Save As… or Export….
To convert DBF, XML, SQLITE, XLSX, SQL, TSV, ACCDB, YAML, MDB, CSV, ODS or JSON files to JA, try Mozilla Firefox or another comparable tool in the "Application Resource Archive" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our JA converter.