It’s visible in the PDF. I have used that extension to mark draft versions of documents. This makes it very obvious and saves you from accidentally handing in a draft. At least back when things were printed out much more often. With PDFs I find that the file name is sufficient.
If you use something Android based for watching YouTube on the TV (some TVs, fireTV stick, etc.), you can: https://github.com/yuliskov/SmartTube?tab=readme-ov-file
I haven’t watched a single Ad on YouTube on TV (SmartTube), mobile (ReVanced), or PC (Firefox + uBlock origin) since it became unbearable… five years ago or so?