Answer architecture round 1: a module's reads sits on its index entry or, for a source without an index, in the load that walks it, the note names default modules, the shipped modules are listed by name, datafiles drops its unused base, and item 195 files the builtins' second parse

pick.go

@@ -19,7 +19,7 @@ import (
 // the read's first-level key, put under the rendering template's key, is one of the name's
 // addressed keys. keptInPick decides this, and readUnder reads it.
 //
-// In data/geo/SE/address.json, {.locality as l} binds l, and {l.street.name} passes the levels
+// In geo.SE.address, {.locality as l} binds l, and {l.street.name} passes the levels
 // "", "street" and "street.name", the last of which is its key. With {l.name} and {l.postal-code.code},
 // l's addressed keys are those three, "name", "postal-code" and "postal-code.code". Where p
 // binds a category whose format reads {first}, and both {p} and {p.first} are read, the {first}
@@ -174,8 +174,8 @@ func (m *drawMemo) enteredFrame(scope *nameScope) *pickFrame {
 // When the pick renders another category, enter takes that category's frames from the pick's
 // memo, and renderFrame finds them and opens no new one.
 // So every read through one pick sees one pick of each name the other category binds:
-// {a.street} and {a.postal-code} in data/sv_SE/address.json read one pick of the name l
-// that data/geo/SE/address.json binds.
+// {a.street} and {a.postal-code} in sv_SE.address read one pick of the name l
+// that geo.SE.address binds.
 func readName(s *drawstate.State, env renderEnv, a arm) readValue {
 	f := env.frameOf(a.named.scope)
 	if f == nil {