What are valid characters for Windows environment variable names and values?

Question

After some reseach, I found out that length limits for names are 255 and for values 32767 characters.

But which characters are allowed for names?
And wh

Answer 1

seems that the only prohibited character is equal ("=") sign - https://msdn.microsoft.com/en-us/library/windows/desktop/ms682653(v=vs.85).aspx

The name of an environment variable cannot include an equal sign (=).