The git commit (in my openid branch) says it all:

Update IkiWiki::openiduser to work with Net::OpenID 2.x

openiduser previously used a constructor that no longer works in 2.x.
However, all we actually want is the (undocumented) DisplayOfURL function
that is invoked by the display method, so try to use that.

This bug affects (my commits show up in RecentChanges as rather than smcv []).

Cherry picked, thanks. --Joey

Relatedly, the other commit on the same branch would be nice to have (edited to add: I've now moved it, and its discussion, to pretty-print OpenIDs even if not enabled). --smcv