Hi, that's a first. Need slow speed. This may work feature Adjusting traffic usage https://www.freedownloadmanager.org/features.htm You can pause them from the download icon. No one seems to want to throttle. There is a paid program Netlimiter. Can not find any Extensions.

Please let us know if this solved your issue or if need further assistance.

I think this program has that option. It can also be set to do the downloads when you want, not just when you send it the data.

This download manager works separately from the browser. The browser tells it what to download, and off it goes.

http://www.freedownloadmanager.org It is a powerful modern download accelerator and organizer for Windows and Mac.