Note that NPMap4 is currently more feature-complete than npmap5

v4 is one mature, accumulated framework; npmap5 is a still-in-progress
rewrite split into small, independently-versioned (mostly pre-1.0)
plugins, several of which aren't merged yet. Worth knowing so we don't
assume v5 already has everything v4 does.

docs/nps-resources.adoc

@@ -257,8 +257,16 @@ own work (a map viewer, not a publisher of NPS-branded content):
 == NPMap4 (the older, Leaflet-based generation)
 
 https://www.nps.gov/lib/npmap.js/4.2.1/ — predecessor to npmap5,
-Leaflet-based, MIT-licensed. Superseded but still live. Two things worth
+Leaflet-based, MIT-licensed. Superseded but still live, and currently
-noting from it:
+*more feature-complete* than npmap5: v4 is one large, mature framework
+(~87k lines, years of accumulated features — baselayer presets, a
+geocoder, popups, etc. all in one package), while npmap5 is a
+still-in-progress rewrite split into small, independently-versioned
+plugins (several still at `0.0.1-x`, pre-1.0), a few of which (`overview`,
+`carto`, `wms`) aren't even merged to `main` yet — see above. v5 is the
+direction NPS is migrating to, not (yet) a feature-for-feature
+replacement; expect this gap to close over time, not to stay this way.
+Two things worth noting from v4:
 
 * *Geocoder control* — example:
   https://www.nps.gov/lib/npmap.js/4.2.1/examples/controls/geocoder-control.html.