I do see a problem with your styling of the layout in your XPKG
It's hard to read
This section on this page
http://xtreeme.org/xpkg/samplemod/install.xml(has a bunch of colored background rings, makes it hard to follow)
Find following code.
ext to fin
In the found code
Find following code.
xt to fi
In the found code
Find following code.
t to f
In the found code
Find following code.
to
Remove found code.
I also don't see any benefit in the code, it's similar to ModX, so I don't really see the point.
I personally think the syntax in ModX is easier to read and follow then in yours, but that's my opinion.