To limit the number of product displaying in minicart, I wrote in
app/design/frontend/myVendor/myTheme/Magento_Checkout/layout/default.xml
below but I see no effect!
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<reference name="minicart">
<action method="setItemCount"><count>3</count></action>
</reference>
</body>
</page>