Convention for naming Properties in Solidwork

Is the procedure for naming Properties in SolidWorks documented anywhere. I have searched help and web but was unable to find any.
For example:

"SW-Cost-StockType@food_processor.SLDASM"

What does the part before and after @ means.

Sometimes there are more than 2 strings separated by @
Sometimes there are more than 2 @ symbols together.

Its all confusing.
Where can I get info about this?