CFAI texts have extra material?

CFAI text seem to give extra information in some sections like Electronic Crossing Networks (ECNs in Equity Investment) which is not even mentioned in an LOS. Is there a possibility these topics could be in the exam ? I mean of course since its not in the optional segment there is a possibility. But has it happened to any L2 takers in the real CFA Exam?

there was a question from this area in last exam

yep, the question was along the lines of which orders would get filled first and at what price. I was thankful I did all of the EOCs in that last month.

Is this a real question? Schweser Notes are notes. They are annotated versions of the full text. Stack up the Schweser material and the CFAI material side by side. Do the CFAI texts have extra material?