Where is the mass center of the Starship second stage?

Starship Flight Test 10. Second attempt (night 25/26 of August, 2025, 6:30 p.m. CT, 23:30 GMT)

A few hours until Starship Flight 10

UPD: Postponed to an unspecified date.
Reason: Problems with ground systems. Fixing.

Starbase at Night — Drone View

Once upon a time two stages Falcon 9 SpaceX met in a port