icetime crash on pcf file

[spth]

The attached .pcf file crashes icetime for me ("icetime: icetime.cc:243: void read_pcf(const char*): Assertion `args.size() == 2' failed.").
I have no idea if I maybe wrote an incorrect pcf file, but it apparently works with nextpnr-ice40 for me.
If my .pcf is incorrrect, icetime should emit a proper error message instead of crashing.
I use the icetime from Debian GNU/Linux testing (would be nice if icetime had a --version option to output a version that I could use in bug reports).
icebreaker.pcf.gz