It is notable that this behaviour isn't described anywhere that I can find in the library manual or the reference manual.  As David says, it applies only to 2.7;  in 3.2 and later, `str` and `repr` are identical.

> a glossary entry be added for 'floating point' which mentions it as a
> 2.7 limitation

That could work.  I *really* don't think it should be linked to from the random docs, though;  this has absolutely nothing to do with the random module, except that the random module happens to contain functions that can produce floats.  Many other modules do that, too.

Another option would be to add the information somewhere in

http://docs.python.org/2/library/stdtypes.html#numeric-types-int-float-long-complex