I never heard of map data feature. Some reported having a small general use data bucket added to their free plan. No rhyme or reason that I'm aware of for an account getting it.
If there were some other limited data use experiments for TextNow free accounts I'd be curious to hear about it.
Most report being able to do a Google search on TextNow free so you can get a location/address but you can't open any links/go any further.