So, I had trouble with fiddler and found your addon, and tested it with Firefox, and it worked! However, I then installed it on Waterfox, and it didn't work. Would you know why?
ps. I did a lot of troubleshooting such as restarting it, reinstalling the addon, etc.
You are receiving this email because you are listed as the developer of an extension for Firefox that uses browser.proxy.register, browser.proxy.unregister, or browser.proxy.onProxyError.
These three WebExtensions APIs will be deprecated starting in Firefox 68 (the console and linter will issue warnings) and completely removed in Firefox 71, currently scheduled for December 2019.
The proxy.register API use a proprietary PAC script because, at the time it was implemented, the proxy filter system was synchronous. It does not implement the standard PAC API, so normal PAC scripts (typically found in enterprise environments) do not work with this API. Now that the asynchronous proxy.onRequest API is available, as well as the proxy.settings API for controlling global Firefox proxy settings, the original API are being deprecated in order to decrease the cost of maintenance for the WebExtensions API.
The proxy.onProxyError API was replaced by the proxy.onError API which has been available since Firefox 60. While our documentation was updated to reflect this, the API was never actually removed from Firefox. Similarly, the proxy.registerProxyScript API, added in Firefox 55 but quickly replaced by proxy.register in Firefox 56, is also being removed.
We encourage you to migrate to a supported API as soon as possible. You can track the deprecation process on Bugzilla.