General problem with naming conventions for WP page address links   In httpenwikipediaorgwikiProgressiveretinalatrophy the link to Siamese is embedded as httpenwikipediaorgwikiSiamesecat When this link is copypasted into a Mac Mail new email for example the link is converted by Mail to httpenwikipediaorgwikiSiamesecat which is invalid Mail replaced the percent character with its hex equivalent Please advise your editors to avoid using special characters or at least to avoid using escape codes in links and anywhere else that copypaste could result in such a conversion For this case the solution is simple the name of the page shoud be httpenwikipediaorgwikiSiamesecat The linking page Progressiveretinalatrophy as coded violates httpenwikipediaorgwikiWikipediaHowtoeditapageLinksandURLs in the paragraph which begins In the URL all symbols must be among  and the paragraph which follows