Something isn't cleaning up after itself. Sorry don't recognize it, but it's nothing to worry about, unless the App is constantly downloading it from the net.
When the Mac starts up it looks in the hidden /tmp folder for files. An App is meant to clean up its temp files before quitting. If it crashes then it may not clean up its files so the Mac moves them to the Trash to allow the User to check them for important data.
A lazy App just leaves them there and they keep bugging the User as they are finding them in the Trash.
You could look in the Recent Items menu to see what Apps you have been using next time it shows up.