https://waf.io/book/ says
By default, the project name and version are set to noname and 1.0. To
change them, it is necessary to provide two additional variables in the
top-level project file
- and waf code inspection confirms that waf itself only will use the top
level VERSION.
Some wscripts will use
bld.env['VERSION']
but that will also just use the value set in the top wscript.