How does one correctly interpret the population-level effect estimate for a monotonic (ordinal categorical) predictor variable.

For example, in the relevant vignette on the topic the simplex parameters are interpreted (as % of total effect) but I don’t see any interpretation for the aforementioned estimate…

I could see it as either the effect of going from level 0 to level n for a monotonic predictor with n levels ~or~ the average effect of going from any level to the next from 1, 2, …, n-1, to n. But I’m really just speculating…

Thanks, Kellen