Customizing Firefox to Read HTTP Proxy Credentials from an fpfile Join my Discord community to learn, share, and discuss together: https://discord.gg/rX2vkNNW This article explains a small Firefox source-code customization for HTTP proxy authentication. The goal is simple: when Firefox receives an HTTP authentication challenge from a password-protected proxy, it first tries to read the username and password from a local fpfile passed through the --fpfile command-line argument. If the file is missing, unreadable, or incomplete, Firefox falls back to its original username/password prompt. This is useful when running automated or customized Firefox builds where proxy credentials should be provided by local runtime configuration instead of an interactive dialog.…