usually indicates a Blu-ray Disc 5 in a multi-disc set, or possibly a scene release naming convention (like a repack/proper version). However, for Yellowjackets S02E07 , the episode title is “Burial” (official title from Showtime).
It looks like you’re referencing a specific file or release label for Yellowjackets Season 2, Episode 7. yellowjackets s02e07 bd5