I have now imported a a LEF
The LEF defines the library information - for example, it defines all available Standard Cell Types (AND2X1, ORX2 etc)
The DEF defines a design - in addition to physical information, it defines all nets, and …
I tried 0.24.10 version, and was able to correctly read in the DEF.
One thing that was unexpected - there doesn't seem to be any instance data imported, or at least I was not able to do a search for instances.