A utility Matchbox shader for Autodesk Flame, Flame Assist, Flare, and Smoke that takes the input alpha channel and outputs it as RGB (white over black) so you can see it. Mostly used for BFX clips on the timeline to see the alpha channel they are exporting - in fact it was written in 5 minutes to help out Greg-Paul Malone with spot-checking lots of BFX green screen mattes.

Grab ShowAlpha from the Logik Matchbook site.