Which SQL Server component is in charge with checking cached execution plans for a given query?

I understand that whenever SQL server receives a query it looks in the cache plan for any matching execution plans for that query. However, most of the resources that I encountered don't specify which component is in charge of this lookup. This article suggests that it's the Buffer Manager, but I failed to find any evidence for this in Microsoft's Query processing architecture guide . On the other hand, the speaker in this presentation (around 42:43) seems to suggest that it's the Cmd Parser. So, which one is it?