Orionis is a low-to-medium contrast theme. Its most prevalent colours are magenta, violet, blue, cyan, and green.
The theme comes in standalone light and dark variants (see further info below).
The font is Iosevka term.
The UI is Atom Material.
Search for orionis-dark-syntax
in Settings > Install > Themes. Or install it directly using the command:
apm install orionis-dark-syntax
Project page: https://protesilaos.com/orionis
Orionis light version: https://atom.io/themes/orionis-syntax
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.