One of the more unusual aspects is the naming convention for types. Most type names use the a_ prefix (e.g. a_statement_ptr), but names beginning with a vowel start with an_ instead (e.g. an_object_lifetime_ptr).

I write comments about what a function does and it's interface before, but comments about the implementation after. Also my pre- and post-conditions go there of course. (I'm mostly writing in C.)

This is also where conditions go in languages with contracts, I like it

This is common in Lisps.

never occurred to me to write a comment there, but it actually looks kind of clean imho. Really old C code looked like

void func(var1, var2) int var1, char* var2. { ... }

perhaps some legacy from that? Probably not, but just first thing that popped into my head since it feels similar :shrug: