Note that it's not my code, nor am I familiar with it. I just had it lying around on my disk to try out Alacritty.

Here's the line in question: https://github.com/jwilm/alacritty/blob/master/alacritty_ter...

I agree 0x1_000 or 0x10_000 would make more sense, but it doesn't look like the actual value used is hugely significant.