New version v1.11.0 of nos2x-fox with support for Firefox mobile.
At this moment Firefox does not allow to install addons on its mobile version the normal way, only a selected few "recommended" addons. However, there is a way to do it.
In the following article there are instructions which involve installing the Firefox for Android Nightly (I think now this works for Firefox Beta for Android too):
I just tested it briefly and seems to be working. So you can use your favorite web clients without entering the private key in each of them 😉.
Please, give it a try and let me know! You can open issues in https://github.com/diegogurpegui/nos2x-fox/issues