When building QtWebEngine with MSVS 2013 and python 3.4 you get error message:
Using Python version ., but Python version 2 (2.7 or later) is required to build Qt WebEngine. QtWebEngine will not be built.
This easily misleads that python version 3.4 does qualifies for this.
Though chromium perhaps does not allow version 3 or more. in prf file I do see a check if it is less than version 3 or not.
lessThan(python_major_version, 3): greaterThan(python_major_version, 1): greaterThan(python_minor_
version, 6): return(true)