I don't know in their case, but I know it's the style used by Hisham Muhammad (author of htop and LuaRocks among other things), and he explained why here: https://hisham.hm/2018/06/16/when-listing-repeated-things-ma...

I’m wondering that too. What happens when a variable is initialized as a consequence of the state of two other variables (which would tend to be a longer statement)?