Comment 9 for bug 228032

I can confirm this is a bug in Ubuntu.
Firefox 3.0 when downloaded from Mozilla site is still shipped with libnspr4.so,
libplds4.so and libplc4.so. These libs are available at least since Firefox v. 1.5 so I think a lot of
developers can depend on them.

I'm developer of Firekeeper extension which depends on these libraries.
To reproduce this bug install the newest Firekeeper:
http://downloads.mozdev.org/firekeeper/firekeeper-0.3.1-linux.xpi
after Firefox restart you will see red '!' in lower right corner that indicates failed installation.
Remove Firekeeper and create missing symbolic links:
ln -s /usr/lib/libnspr4.so.0d /usr/lib/libnspr4.so;
ln -s /usr/lib/libplds4.so.0d /usr/lib/libplds4.so;
ln -s /usr/lib/libplc4.so.0d /usr/lib/libplc4.so;
Install Firekeeper again. It should work fine.
I don't know what was the reason for removing these links. Is seems other developers
have also problem with this issue:
http://groups.google.co.uk/group/gears-eng/browse_thread/thread/e8942a7c15f2bc72/698059fe9397beb6?lnk=st&q=libnspr4.so+ubuntu#698059fe9397beb6

The workaround would be to link against libxul.so which on Ubuntu depends on /usr/lib/libplds4.so.0d,
/usr/lib/libplds4.so.0d, /usr/lib/libplc4.so.0d.
But it is not convenient solution, since libxul is not available in Firefox 2.0 so it would require to ship different versions of extension for FF2.0 and 3.0.
It would be much simpler if these libs are just available in Ubuntu under standard names.

Cheers,
Jan