DXP is the commercial & SLA-supported product, Portal is the Open
Source release.
So, if one can speak of
"included", Portal would be included in DXP (and indeed,
there are a few extra modules in DXP, e.g. for the commercial app
servers and databases).
But as of the documentation on learn.liferay.com - you should be able
to use it for both variants, unless it's explicitly stated that
something is "DXP only".
