Hmm... I see https://github.com/antmicro/openlane/blob/1185510efbe8d2a7dd1e30ac6bd77808c98dd3d7/scripts/synth.tcl#L21-L22 does a

yosys -import

after loading a plugin. What does

yosys -import

do? It doesn't seem like a valid command within yosys, nor is it a valid command within tclsh. Is there any documentation on it?