theres a file called
informationpanelcontent.cpp
on line 144 is this
layout->addWidget(m_metaDataArea);
so I seem to remember you can either comment this out or add a line after it:
m_metaDataArea->hide();
which just hides it.
I did want to get fancy and add a short cut to hide it but I got lost in the weeds and never did.
I see the development of Kiview is active and looks like it’s going to be really good so I’ll not bother, which is a relief as I suck at coding.