jpm run broken in Firefox 47 beta 3 onwards

[Trevor Johnston]

Hi mozilla-labs-jetpack,

It seems that, from Firefox 47 beta 3 onwards, jpm run no longer does "the signing thing" - meaning the extension under test (silently) fails to load.

I can't find any documentation on how to override; am I missing something? I'm afraid switching to developer editions may not work for us since we rely on jpm run to be able to quickly test compatibility with any version of Firefox (we can change our testing setup I guess but I'd prefer maintain parity with our Chrome testing).

Many thanks for any help.