Use "firefox -app" with Firefox 32.

Go to https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=681518#13

Click on 681515.patch

Press "t"

Errors on STDOUT:

NS_ERROR_NOT_IMPLEMENTED: Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED)
[nsICacheService.createSession]
cache_entry_clear()@chrome://conkeror/content/cache.js:56
override_mime_type_for_next_load()@chrome://conkeror/content/mime-type-override.js:81
_co_impl__send()@chrome://conkeror/content/coroutine.js:415
Handler.prototype.process()@resource://gre/modules/Promise.jsm ->
resource://gre/modules/Promise-backend.js:863
this.PromiseWalker.walkerLoop()@resource://gre/modules/Promise.jsm ->
resource://gre/modules/Promise-backend.js:742
null()@null:0

Happened with current git HEAD (8a26fff5896a3360549e2adfbf06b1d57e909266) as available in the conkeror
nightly built .debs.