In r, when predicting with newdata=data.frame(1) what does it mean?

My here and now question relates to a weibul model with survreg, but my question is more general about r's predict().

Example:

library(survreg)

# weibul model with survreg and veteran data
weibul_model <- survreg(Surv(time = time, event = status) ~ 1, data = veteran, dist = 'weibull')

# expected value? Or what?
predict(weibul_model, newdata = data.frame(1))
predict(weibul_model, newdata = data.frame(10))
predict(weibul_model, newdata = data.frame(100))
predict(weibul_model, newdata = data.frame(1000))

All 4 calls to predict return the exact same number, 120.6804.

What is this number, how do I interpret it?