It's a piece of crap. I've used it for several years, and have managed to get by. Now, however, if you try to download a newer version (I currently have 126.96.36.199) from a 64 bit debian machine you end up on a page that says:
Luckily, there's apparently an open-source project, fribid, which may be able to replace bankid/nexus personal for those who don't want to get stuck with 32 bit linux (seriously -- why does 4.17 work on 64 bit and future versions won't? And why won't you let me download an older, supported version? And why can't I chose what version I download? 32 bit windows from a 64 bit linux box -- and vice versa -- SHOULD BE POSSIBLE)
tar -xvf fribid-1.0.0.tar.bz2
sudo make install
I didn't have to do anything to 'install' it beyond that. Navigating in iceweasel to a website requiring bankid started fribid as it should and prompted me for the key file.
I can't explore the functionality beyond this, as fribid can only read keys downloaded with bankid/nexus v 4.10 or earlier -- pk12. The clincher here is that you can download the keys using fribid to begin with instead of first downloading them with bankid.
ERROR: Unsatisfied dependencies:
gtk+-2.0 >= 2.12
sudo apt-get install libgtk2.0-dev