protected static DBTraceSpaceKey unpackSpaceKey(long id, Language baseLanguage,
			DBTraceThreadManager threadManager) {
		int spaceId = unpackSpaceId(id);
		AddressSpace space = baseLanguage.getAddressFactory().getAddressSpace(spaceId);
		if (space == null) {
			return null;
		}
		return space.isRegisterSpace() ? unpackRegSpaceKey(space, threadManager, id)
				: unpackMemSpaceKey(space, id);
	}
For non-register space:

{@code
+---12----+----52----+
| SpaceID |    Key   |
+---------+----------+
}

For register space:

{@code
+---12----+----32----+----8----+--12--+
| SpaceID |  Thread  |  Frame  |  Key |
+---------+----------+---------+------+
}
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/bookmark/DBTraceBookmarkManager.java