I’m starting to write content for the wiki and have started with the page about the runtime since most of the issues that are reported against it are often incomplete and cannot result in a proper fix.
http://wiki.lutris.net/index.php/Runtime
This page explain what the runtime is, how to disable it and more importantly, who to debug issues with it.
If there are any additional questions that are not covered on this page, fell free to ask questions and I’ll complete or clarify the wiki page 
