Last modified: 2014-05-14 19:24:23 UTC
The citation tool recongizes a citation template that starts like this: <ref>{{cite web|url= It does not recognize one that starts like this: <ref>{{cite web |url= The only difference is the (very common) addition of a space before the parameter. It should understand both of these.
I fixed this in https://gerrit.wikimedia.org/r/#/c/132725/ without realizing it.