I found this about iceweasel, which inclines me to believe that you remembered it correctly, and the grandparent was just mistaken about the name:
> In August 2005,[11] the GNUzilla project adopted the GNU IceWeasel name for a rebranded distribution of Firefox that made no references to nonfree plugins.
> [...]
> The GNU LibreJS extension detects and blocks non-free non-trivial JavaScript.