Do they exist or I need to read billions of lines of /verbosity:diag parameter lines? Maybe you have other solutions?
The MSBuild Sidekick has some debugging functionality along with some other good stuff.
The output logs are the primary tool for diagnosing problems with MSBuild scripts and they will pretty much give you all the details you might need. If you are tracing a specific problem, you can lower the verbosity level and add some explicit information messages to your build:
<Message Importance="normal" Text="Some diagnostic info incl. property values" />
You can do real debuging if you write custom build steps and attach to the MSBuild binary.
First of all though, what is the real problem you have. Understanding what you are trying to achieve and where you encounter problems might help.
I would also recommend reading Inside the Microsoft® Build Engine: Using MSBuild and Team Foundation Build - this book should give you plenty of answers that should stop you from having to diagnose the project in the first place.