It's the same meme - a stack of pancakes as a visual pun on "software stack"/"full stack." Not the only place I've seen that before, either - I've seen the same idea on T-shirts and laptop stickers.

Funnily enough, I went to sequelpro.com/legal to find that while their software is under the MIT license, as opposed to the more restrictive GPL license used by BTrDB, the website specifically calls out the icon as property of the project and its use is disallowed in forks. So, it looks like they really would care more about the logo being ripped off more than anything.