Apparently this is legal markdown, though unusual syntax for a link:
- \[Branchable](http://www.branchable.com/ "Ikiwiki hosting")
+ [Branchable](http://www.branchable.com/ "Ikiwiki hosting")
If that is put on a translatable page, the translations display it not as a
-link, but in the escaped form that appears above.
+link, but as plain text.
Probably a po4a bug, but I don't see the bug clearly in the gernerated po
file: