From FIXwiki

FIX Message MarketDefinitionUpdateReport (MsgType=BV)

MsgType	FIX Specification	First introduced	Deprecated
MsgType=BV	PreTrade messages - MarketStructureReferenceData	FIX.5.0

In a subscription for market structure information, this message is used once the initial snapshot of the information has been sent using the Market Definition message.

Message Contents By FIX Version

Notes

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Links from FIXwiki pages to relevant discussions on the FPL site are very valuable.

For example if you were writing a clarification on how to specify the "quantity" of an order in FIX, you might add the
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