What is EDID manager?

In plain language

Normally the EDID a source reads is whatever the next device in the chain hands over. An EDID manager takes that job away from the chain and gives it to you. It presents a chosen, known EDID upstream, and it keeps presenting it whether or not the display is on, whether or not the receiver is awake, and regardless of what a switch in between decides to do.

Why it matters in your setup

Three things become possible once the EDID is under your control. You can make a capability visible that the chain was hiding — 4K120 or VRR that never got advertised. You can hide a capability on purpose — forcing a source down to a format the chain can actually carry. And you can keep the EDID stable, so a source does not renegotiate every time a display sleeps.

It is worth being clear about the limits. An EDID manager changes what is advertised. It cannot add a decoder to a TV that has none, and it cannot make a cable carry more bandwidth than it physically can. If you advertise 4K120 into a chain that cannot carry it, you get a black screen rather than a picture.

What the DR HDMI 8K does with it

That is exactly what the DR HDMI 8K is. It manages, emulates and repeats the EDID at up to 48Gbps, with three working modes: copy the sink EDID as-is, load one of 100 predefined tables, or copy the sink EDID and modify selected flags. Everything is visible on the OLED and in the browser interface, so you can see the effect of each change immediately.