AviUtl
From Misc Data Digs
AviUtl has some hidden messages scattered throughout various files. For example, this can be found in the main executable:
萌える動画作ろうぜヽ(`Д´)ノ AviUtlはツンデレ仕様となっております(´・ω・`)
Let's make a kickass movie.ヽ(`Д´)ノ AviUtl is noted to be a tsundere (´・ω・`)
(Source: Wandering Golden Beard)