How to interpret BRICS fragments
Cutting a molecule (expressed with SMILES strings) into fragments yields sub-structures.  Typically these fragments can't be considered as molecules for their open, non-bonding valencies.  Derived from SMILES, it is then the SMARTS notation which is used to represent them, or to search with this notation of sub-structures in databases, e.g. in bioinformatics.
Open Babel supports the display of SMARTS-encoded fragments with branching points marked by an asterisk. The phenyl group, [16*]c1ccccc1 thus is shown as:

Consequently, bidental fragments are represented with two asterisks, e.g., [4*]CC[4*]: