Consistency is important, even more so when writing open-source code, since the code belongs to millions of eyeballs, and bug-fixing relies on these teeming millions to actually locate bugs and understand how to solve it.
This is why, when writing anything for HumHub, be it a theme, a module or a core patch, you should strive to follow the following guidelines. They are the ones that the HumHub developers adhere to, and following them is the surest way to have your code be elegantly integrated in HumHub.
In short, having code consistency helps keeping the code readable and maintainable.
We keep PSR-1 and PSR-12, along with a few nice details from Yii2 Core Framework.