+(In)compatibility notes:
+
+- `po_link_to => negotiated` provides no useful behavior if `usedirs`
+ is disabled; this option combination is neither implemented nor
+ allowed
+- `po_link_to => negotiated` provides no useful behavior if the web
+ server does not support Content Negotiation
+
+### Link to current language
+
+If `po_link_to` is set to `current` and the destination page is either
+a translatable page or a translation, `[[page]]` links to the current
+page's language, *i.e.*:
+
+- `foo/page/index.LL.html` if `usedirs` is enabled
+- `foo/page.LL.html` if `usedirs` is disabled