This refers to 8589 U+2192 which is really \rightarrow In the html it just falls through so makes a short arrow but in the TeX stylesheet this is mapped to \longrightarrow.
As far as I recall this was due to the unreliability of fonts on the web last century. U+2192 was in Unicode 1 so fairly safe to assume would work but U+27F6 was Unicode 3.2 so later than OpenMath 1 and MathML 2 and not widely available.
Now however this shouldn't be an issue even without special math support I would expect most people can see a short and long arrow here:
2192 → 27f6 ⟶
So I propose to change the entity to use a standard ⟶ entity (as would work in html5 anyway) which would mean that arrows in the HTML version of the standard got longer. There are 32 of them in the spec.
The old DTD (and copied into the new DTD made for issue #41 ) has always had the comment
<!ENTITY longrightarrow "<mo>→</mo>"><!--dpc: short, actually -->This refers to 8589 U+2192 which is really
\rightarrowIn the html it just falls through so makes a short arrow but in the TeX stylesheet this is mapped to\longrightarrow.As far as I recall this was due to the unreliability of fonts on the web last century. U+2192 was in Unicode 1 so fairly safe to assume would work but U+27F6 was Unicode 3.2 so later than OpenMath 1 and MathML 2 and not widely available.
Now however this shouldn't be an issue even without special math support I would expect most people can see a short and long arrow here:
2192 → 27f6 ⟶
So I propose to change the entity to use a standard ⟶ entity (as would work in html5 anyway) which would mean that arrows in the HTML version of the standard got longer. There are 32 of them in the spec.