It’s easy to assume that’s blood in the package. But it isn’t.
The story of what’s REALLY in that liquid is actually pretty interesting.
The red goop has even got a name: ‘Weep’ or ‘purge’.
Ice crystals (from the freezing process) break up the muscle cells.
When the meat thaws again, the compounds released from the muscle mix with the now-liquid water.
The video fills in the rest.