All documentation are here: https://www.axeslive.com/support/documentation.htm
if you click 4.2.1 in particular you get directed here: https://axesdocs.lansa.com.au/index.php
some detail are here under features: https://axesdocs.lansa.com.au/index.php/feature-help-2
but the extensions or functions listed in that particular way, I cannot find it anywhere, the documentation for this product is oriented to a more lead by example way... if you take a look to the axextensions.js file:
you can get a peek about what extensions are available for aXes.