I’m not “someone from Purism” but here are my thoughts.
My understanding is that the intention is not to do, or support, HDMI, so the question for HDMI doesn’t really apply. My understanding is that the underlying hardware can do HDMI, with a blob, but therefore it will not be used and there will be no connector for it anyway.
Video out will be via DisplayPort over USB-C (in one of USB-C’s alternative / alternate / alt modes). The question then arises as to whether that combination, including the monitor, will support HDCP (or DPCP) with DisplayPort.
On top of that … since many people have a monitor that does not support DisplayPort over USB-C anyway, they would be trying to use an adapter that converts DisplayPort over USB-C to … DisplayPort on a conventional DisplayPort connector / HDMI / DVI / VGA (I assume VGA requires an active converter). So the adapter becomes a part of the puzzle / point of failure / variable.
I’ve purchased (for another purpose) a display that does support DisplayPort over USB-C but when I get my L5 I will at least give it a try.
I won’t be testing HDCP though. It is of zero interest to me as long as it doesn’t get in the way. With the L5 I don’t think it is going to be possible to test HDCP.
If you want someone from Purism to respond, best to ask Purism directly via email - and to add detail to your question.