Well I couldn't resist, gave it a try and it works fine !
- up-to-date Manjaro distro, which provides Palemoon 28.0.1
- conkeror cloned from github
Works like a charm, only glitch being that gmail reverts back to a
simplified html version ; other https sites can be browsed normally.
Thanks for the heads up, I wouldn't have thought to try again conkeror
so many months later, and having quite a lot of work to do at the
moment grabbing images from pages among other things, this is going to
be useful.
Cheers