So the vm seems to be hierarchy_macros.vm
where I see:
#set ($treeParams = {
'class': 'breadcrumb-tree',
'limit': 10,
'links': true,
'openTo': $openToId,
'root': $rootId,
'showTranslations': $xwiki.isMultiLingual(),
'showWikis': $showWikis
})
It’s the value 10
that you want to change probably.