The Presonus VST3 extension allows it to ask the host for the location of the current project file and the currently used audio file directory. This is a handy feature for one of our products, enabling an optional convenient feature to the user. I tried it with Reaper where it works fine, Studio One should of course also work, however there are hosts out there that don’t implement this extension 
Do you know of other any non-standard extensions to make this possible in major hosts? And also, is there any overview which VST3 hosts out there implement the Presonus extension?
I’d be especially interested in a solution for Logic Pro and Nuendo/Cubase