Either of these is fine with me. I am just trying to allow the browser to break the string "machine.site.domain" at the '.' over a line-end. If there is a hyphenless way to do this, that
would be great.

Some print-formatters have routines to do this but I don't know
of one for XSLT, and I don't know how many browsers will honour
the relevant non-spacing break character (Unicode expert needed
here).

This content is inside of a table element and am I just trying to give the browser an opportunity to reformat the string.

I would also like allow the browser to break lines at a "/".

That would be one of the permissible breakpoints, but you run
into trouble if it breaks the "method" component as in http:/
/www.w3.org in the "wrong" place. This is why an algorithm is
needed, not a simple insertion.

Is there a difference in what is returned by xsl:value-of when called for an element vs an attribute?

As a concrete example, the attribute value

./Common/Testing/Cxx/ObjectFactory.cxx

should have been translated to

.­/Common­/Testing­/Cxx­/ObjectFactory.cxx

but becomes

.A-/CommonA-/TestingA-/CxxA-/ObjectFactory.cxx