All of the editions (Laforgue Edition, Machen Edition, Conrad Edition) are in the Public Domain in most countries. Changes to those editions (mainly links and formatting) will be kept in the Public Domain as well.
Except where otherwise noted, everything else (glossary, annotations, etc.) is licensed under the CreativeCommons Attribution-ShareAlike 3.0 Unported license.
An exception is e.g. the table of contents of the Trask edition, which is copyrighted (see notes on that page).