There is not an option to limit your bandwidth. Though I don't see how that would reduce your data consumption. Visiting a site that is 2MB will download the same amount of data on 2g, 3g, 4g, hpsa, and lte. The only difference will be in the amount of time it takes to download the 2MB.

don't want to decrease my bandwidth I want to increase it. please download photon browser for Android and see their settings. supposed to speed up things by increasing bandwidth if I have fast download speeds. not to worry Firefox is and will remain my browser

Sounds like they are doing the same thing Opera Mini does. This routs all your browsing through a server controlled by the browser. This allows the browser provider to see most if not all of the content you view.

Routing all your browsing through Mozilla controlled servers is not in line with the privacy ideals of Mozilla. https://www.mozilla.org/en-US/about/manifesto/ Principle number 4