diff --git a/site/public/documentation/builtin_borders.md b/site/public/documentation/builtin_borders.md
index f849c95..1d105e5 100644
--- a/site/public/documentation/builtin_borders.md
+++ b/site/public/documentation/builtin_borders.md
@@ -1,7 +1,7 @@
 Borders Plugin
 ==============
 
-The `borders` plugin renders the borders around (and between) countries. It uses TopoJSON data published to `planet.plugins.topojson.world` by the [TopoJSON plugin](/documentation/builtin_topojson.html).
+The `borders` plugin renders the borders around (and between) countries. It uses TopoJSON data published to `planet.plugins.topojson.world` by the [TopoJSON plugin](/documentation/builtin_topojson.html). It uses the feature at `objects.countries` in the TopoJSON object to calculate the borders.
 
 API
 ---
diff --git a/site/public/documentation/builtin_land.md b/site/public/documentation/builtin_land.md
index 15b2c18..ee35866 100644
--- a/site/public/documentation/builtin_land.md
+++ b/site/public/documentation/builtin_land.md
@@ -1,7 +1,7 @@
 Land Plugin
 ===========
 
-The `land` plugin renders Earth's landmasses. It uses TopoJSON data published to `planet.plugins.topojson.world` by the [TopoJSON plugin](/documentation/builtin_topojson.html).
+The `land` plugin renders Earth's landmasses. It uses TopoJSON data published to `planet.plugins.topojson.world` by the [TopoJSON plugin](/documentation/builtin_topojson.html). It uses the feature at `objects.land` in the TopoJSON object.
 
 API
 ---