The point is not that Shumway is directly connected with pdf.js, but rather that the wording in its descrition suggests pdf.js is no longer a research project.
pdf.js was the brainchild of Andreas Gal, now our CTO but at the time a cofounder of Mozilla Research along with Brendan Eich and me. That project started briefly in Research but was shepherded to product pretty quickly.
Shumway is a separate project but similar in spirit. It's not a converter per se, but rather an emulator including a full ActionScript Bytecode (ABC) JIT, implemented in pure JavaScript. Right now we are interested in getting Shumway to the point where it can be used in Firefox as an alternative to the native Flash plugin for certain kinds of web Flash content, to provide better security, stability, and performance. Over time as Shumway matures the ultimate goal would be to eliminate the need for the Flash plugin entirely, but we'll walk before we run.
But Shumway is usable as a standalone project as well, and others have begun taking notice. For example, Prezi has invested in Shumway as a library for rendering vector graphics:
Separate projects. But, pdf.js is integrated into Firefox and is past the research stage. I believe they're just sort of saying, "Hey, we made that other seemingly impossible idea work when we made pdf.js actually work pretty well, so you probably shouldn't laugh when we say we're implementing Flash in JS and HTML5."
