What is Mozilla CFG byte shift 13?
Firefox AutoConfig files may use reversible byte shifting by 13. This is obfuscation, not encryption. The configuration can also be configured without shifting.
Firefox configuration, made simple.
Decode, edit and build Mozilla AutoConfig files with a clean workflow. Private browser-based tools and instant downloads.
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Decode your Mozilla CFG file instantly
Upload a Firefox mozilla.cfg file or paste its contents. Decode with legacy byte shift minus 13, or inspect plain text without conversion.
Maximum file size: 10 MB.
Processed locally in your browser. Nothing is uploaded.
How it works
- Choose Decode (-13) or Encode (+13).
- Upload a file or paste source text into the editor.
- Convert, inspect editable text when available, and download the output.
Encoded CFG bytes can be binary and may not display as readable text. Download binary results to preserve data.
Frequently Asked Questions
Does the tool decode all CFG formats?
No. Many games, servers and applications use the CFG extension. This specific tool supports Firefox AutoConfig byte shifting only.
Are files stored?
The quick decoder on this page runs locally in your browser and does not upload files. Other tools may use a server endpoint; avoid putting secrets in configuration files.
Made for a smoother workflow
From an old mozilla.cfg file to a ready-to-use AutoConfig setup, find the right tool for each step.
Mozilla CFG DecoderDecode legacy Firefox mozilla.cfg files using byte shift minus 13 or plain-text mode.Mozilla CFG EncoderEncode AutoConfig text using byte shift plus 13 or export plain CFG.Online CFG EditorEdit Mozilla configuration scripts in a private browser-based editor.CFG ValidatorRun preliminary structural checks on Firefox AutoConfig scripts.Firefox AutoConfig GeneratorGenerate a basic mozilla.cfg file with a matching autoconfig.js loader.