Answer stability round 1: the docs say the US tenth is drawn from every place, a capital matches by a name only one place in its state carries, and the test comment says what it checks

CHANGELOG.md

@@ -95,10 +95,10 @@ replacement, and each removed path, column or flag.
   `en_US.address.street` no longer carries `name` and `suffix`, and a locale's `address`
   reads its country's `geo` module. Every Swedish postort the import can place and give
   a street ships with all its streets. Of the US incorporated places that hold most of
-  some postal code's land, every state capital but Honolulu, every place of 100,000 or
-  more, and a tenth of the rest drawn by population down to villages of a hundred people
-  ship, so a smaller city may be missing; each carries a quarter of its streets, at least
-  ten.
+  some postal code's land, a tenth drawn by population down to villages of a hundred
+  people ships, and every state capital but Honolulu and every place of 100,000 or more
+  beside, so a smaller city may be missing; each carries a quarter of its streets, at
+  least ten.
 - `{date(from,to,'layout')}` and `{time('layout')}`: a second between two days, or
   within one, in a single-quoted Go layout, drawn in UTC; `from` may equal `to`.
   `sv_SE.date`, `en_US.date`, `sv_SE.time` and `en_US.time` render through them, so