Author: mjiang
Description:
An apostrophe (single quote) in url can be either a single letter ' or three letters %27. They should be equivalent, but the following two urls point to two different versions of the same page:
http://en.wikipedia.org/wiki/K%C3%B6nig%27s_theorem_(graph_theory)#Proof
http://en.wikipedia.org/wiki/K%C3%B6nig's_theorem_(graph_theory)#Proof
The first url points (correctly) to the most updated version. The second url points (incorrectly) to an older version. Open two windows and compare, in particular, the section "Proof".
Google "Konig's theorem", and you will see the first hit gives the url with a single letter ' for the apostrophe. If you follow the second google hit instead and choose "(graph theory)" from the Wikipedia disambiguation page, you will get the url with the three letters %27 for the apostrophe.
Version: unspecified
Severity: major