[orca-list] Any workaround to install externel *.xpi files for tB with Orca?

[Jakob Herrmann <jhlists infosprinter com>]

Hi,

due to compatibility issues with the new Thunderbird version, I have to 
reinstall an addon manually from a created xpi archive. However, I can't 
find an install button or something like that in the so called addon 
manager (which is crap and hardly accessible apart from that). There is 
supposed to be a kind of widget which provides a menu with functions 
like install from file or so, but I can't find it with Orca and even 
sighted people helping me were not able to find anything. Is there any 
alternative workaround to install the file, i.e. for folks like us?

Thx for help and cheers,
Jakob