Does the SMILES grammar include the | symbol ?
wdiwdi [ Editor ] from Frankfurt am Main, Deutschland
No, not officially,
You are seeing a Cactvs toolkit extension for a “complex bond”, i.e. a bond which does not count electrons, and lacks a defined bond order.
This could be disabled in the toolkit, though, so this is not a feature forced onto the world (talk to the NCI resolver people if this is an issue for you). But it helps for example in faithfully representing PubChem structures, which internally have the concept of various bond types.