Make sure IPFS & co in addons are shoved up through Tor and don't leak in ESR60

Starting from FF59,

https://blog.mozilla.org/addons/2018/01/26/extensions-firefox-59/

Support for Decentralization Protocols

Mozilla has always been a proponent of decentralization, recognizing that it is a key ingredient of a healthy Internet. Starting with Firefox 59, several protocols that support decentralized architectures are approved for use by extensions. The newly approved protocols are:

• Dat Project (dat://)
• IPFS (dweb:// ipfs:// ipns://)
• Secure Scuttlebutt (ssb://)

Firefox itself does not implement these protocols, but having them on the approved list means the browser recognizes them as valid protocols and extensions are free to provide implementations.

Firefox will allow addons to support IPFS, ..etc. There's a need to be sure that all those things when implemented in addons are shoved up through Tor and don't leak.