If i am manually selecting topic from the left side documentation tree firefox will return "The address wasn't understood" because the link for example "c:/Program%20Files/Unity%205.0.0b15/Editor/Data/Documentation/en/Manual/ProjectView.html" must include "file:///" beforewards local file locations links, using forward and backward icon will work though. Strangely on chrome it will work fine, chrome seems automatically add "file:///" to all local file links. Are unity documentation guys never test it on firefox ? or is it a bug on unity b15 documentation ? Scripting references seems not affected, only unity manual being affected.