Found this out when testing lineups for Brimstone. Certain abilites for different characters use the same physics model, follow the same trajectory and land in the same spots. For example, Brimstone's molly, viper's snakebite and sage's slow orb all go the same speed and follow the same arc through the air. The lineups for these agents effectively transalte to each other (although keep in mind that the brim molly bounces a bit).

Why this information is relevant now is that Viper's toxic cloud (smoke) and Killjoy's nanoswarm (that's her molly) follow the same path. Since the latest update you can see where the viper smoke will land on your minimap in a custom game with cheats. So now it's easier than ever to find clever lineups for KJ's mollies, since they land in the same spot as indicated on the minimap with viper's smoke.

Whether it is to flush out opponents from positions, deny a plant or retake, or even ult-trap people, the KJ molly can be very impactful. This is one of the best ways to take your Killjoy game to the next level, putting your opponents into consistenly bad positions. I cannot stress how useful this new lineup tool is.