I'm pretty sure we don't have any digital storage media that last 1000 years, or even 100 years. There's no point even trying to read it that far in the future; it's completely gone.
One could also etch the data on a silicon wafer that could be read with a microscope (maybe indexes and retrieval instructions readable with an optical microscope, data with an electron microscope).
I didn't miss that point, because they never made that claim. At least in the linked video. If they had, it'd be bullshit.
"This vault contains the 188 reels of hardened archival film which will preserve the 02/02/2020 snapshot of every active public GitHub repository for 1,000 years."