-# Copy addonfile $1 from the TEMPLATE_DIRECTORY/compat (if exists),
-# or from $2 (the system path), or warn about the missing file.
+# Copy addonfile $1 from either
+# * the chroot (via $2, the system path),
+# * or from TEMPLATE_DIRECTORY/compat (if exists),
+# * or from the host system (again, using $2),
+# or warn about the missing file.
+#