What does the "IsSpace" linkset do?

[mgroetan]

I'm a datafile editing noob and have seen that units (at least Necrons) have a linkset of either "IsSpace" or "IsSpaceW". What purpose do these have?
When I tried setting the "IsSpace" linkset on a new unit I added (from ForgeWorld), Army Builder complains when recompiling, saying that there's a reference to a non-existing linkset.

[mgroetan]

Update:
I still wonder what it does, but I've found out that it doesn't start with a capital "I" ("India"), but rather a small "l" ("Lima").

[deano]

I dont know either.  I generally leave it when I come across it.  (Waits for Homer_S)

[Homer_S]

It adds some spaces in to the options panel for a typical unit. Take a look in the general file where it is defined.

Homer