Indicate the next beginning of town somehow on the route.
On the map and/or with info saying "beginning of town in 500m ... 400m ... 200m" etc.
Or even just one popup saying "town in 300m".
Or just with a marker on the map! That would also suffice.

I have wanted this feature for years.
Very hard to estimate when in an unknown area.
For those of us mindful about eco driving, there is no point in pressing the gas pedal up until the sign and then braking suddenly from 90km/h to 50km/h.

It would be nice to know when to depress the gas pedal (or disable cruise control) to have the car slow down form 90km/h to about 60-50km/h. Saves a lot of gas and a lot of brake pad.

Can also be a safety feature since pedestrians are much much more likely to appear at inhabited places than out-of-town.

Easy to mark since the speed limit changes (in europe usually from 80-90-100 to 50).