Firefox userChrome script

1. Open external downloader directly from Firefox's native download asking dialog. Adds a button to call system command and pass argument to it. (Modify it yourself to use your downloader)

2. Show automatically-started download progress

Tested on Firefox 153.

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This repo only contains the specific function, doesn't contain the code to enable userchrome scripts.

For how to enable, see: (also more of my scripts)

https://garywill.github.io/#Firefox-userChrome-CSS-or-JS