Browsing through the testsuite, I find Firefox 1.5 almost perfect!
In some cases it's showing up errors in the sample images, e.g.,
Presentation/TokenElements/mi/mimathvariant14.png (displayed in
mimathvariant.xml).
I'm finding inconsistency in the current rendering of the following
presentation language:
<math xmlns="&mathml;">
<mi>x</mi><mo>′</mo>
<mo>+</mo>
<mi>x</mi><mo>″</mo>
<mo>+</mo>
<mi>x</mi><mo>‴</mo>
</math>
″ and ‴ as postfix operators are by default raised, while
′ is not. My recollection is that ′ was also raised in
the early days of Mozilla MathML. In fact, see the 6th term in
the testsuite image:
http://www.w3.org/Math/testsuite/testsuite/Topics/Primes/primes1.xml
Is the inconsistency intentional?
-- Bill
P.S. I wonder if it might not also be reasonable to provide raising
in the cases of <mi>x'</mi> or <mi>x′</mi>.