A star is a billion light years from earth. Today, we see the light
it emitted a billion years ago.

A billion years ago, it was more massive than it is today. That
star's gravity is acting on the earth today, ever so slightly.

Question: Is the gravity we "feel" from that star a result of its
billion-year-ago mass, or its mass today?

[Not a quiz; I don't know the answer, and have been intending to ask
this for some time.]