2 operators I have a question about...

[webmasterpdx]

I remember encountering the operator =< before and I can't remember what it does again...it's one of those undocumented ones....can someone remind me?
Also, I encountered this in another site and it's unclear if this is an operator or the person was trying to use this as a notation in the article....but it was the := followed by an arrow -> (single character)....???
Thanks
-Donald

[parisse]

=< is the storage operator by reference in CAS lists (and derivatives objects like matrices)