Here is a patch for page.tmpl to add these landmarks.
-{{{diff --git a/templates/page.tmpl b/templates/page.tmpl
+
+> This can't be applied as a patch as-is because it's based on Tails'
+> modified `page.tmpl`, but I get the general idea. A reviewer will need
+> to check the ARIA meanings of those roles to confirm that they
+> are appropriate (I haven't done that yet). [[!tag patch]] --[[smcv]]
+
+[[!format diff """
+diff --git a/templates/page.tmpl b/templates/page.tmpl
index 5efad1a..cb76590 100644
--- a/templates/page.tmpl
+++ b/templates/page.tmpl
<TMPL_UNLESS DYNAMIC>
<TMPL_IF HTML5><nav id="pageinfo"><TMPL_ELSE><div id="pageinfo"></TMPL_IF>
-}}}
+"""]]