Are files uploaded?
No. The tools read files using browser APIs. There is no upload API. Downloaded output is created in your browser. Hosting still receives ordinary page requests.
Can every CFG file be edited?
Only text configurations within the 2 MiB and 30,000-line limits. Some CFG files are binary or proprietary and need their original application. UTF-16 text is supported; unknown binary content is rejected when detected.
Does validation guarantee a working file?
No. JSON is parsed strictly. INI and key/value checks report basic structure and duplicates. YAML, TOML, shell and Mozilla modes only offer basic checks. Application-specific keys and values are not verified.
Will my work be saved?
Only in the current tab’s memory. Download a copy before closing or reloading. The original file on disk is never overwritten by the site.
Is Mozilla encoding secure?
No. It adds 13 to each byte modulo 256 and is easily reversible. Use it only for compatibility with the relevant Firefox AutoConfig loader setting, never to protect secrets.