I see two possibilities:
- it's injected via Partial Designs - some partial design has it defined and when layout is composed it is injected to the page. The fact that placeholder matches causes this rendering to pop up inside
- Ambient Video Container is a "snippet" - there is a change that someone made a clone of regular snippet rendering and presentation is pulled from the Ambient Video Container datasource (see how snippet works here)
You can make a quick test to eliminate 1
Try to move Ambient Video Container to a different placeholder (i.e from
footer, save page and see if Video rendering is still there).
If not, it's probably case 1 if it remains there it's probably 2.
If 2 is true - open datasource dialog of Ambient Video Container find this datasource item, them verify if Video rendering is present in layout details.
That might be tricky if someone had fantasy and used nested snippets ...
Another way could be finding the rendering by UID.
Open Chrome dev tools and try to find element with this name:
scLayoutDefinition, it should contain layout definition in JSON.
Try to find your Video rendering and get its UID.
Now you can find your rendering in the content using preferred search method (c# code, powershell, SQL), basically your goal is to find and item which contains your UID in one of the fields (I hope you know that presentation is stored in these fields as XML):