This convention is used within the type system throughout kdb+. i for 32bit integer, j for 64bit int, h for 16bit int, e for real, f for float etc. Anyone who knows q will automatically recognize these types in the the c-api. They'll also recognize the ref count r, the type t and experienced c programmers will recognize the trailing array idiom.
K is only hard if you try to read it without first studying it. Looping is achieved through adverbs. The key to it is understanding what is a noun (data), verb (operator/function) and adverb (takes a verb, creates a new verb to be used infix). A verb with a noun to its right is a dyad if there is also a noun to its left, and is otherwise a monad. If it is needed, the monad can be specified by appending a colon to the right of the symbol. Fortunately, most kdb+ developers program in Q, which has a bunch of helper routines defined in k, and assigns monads to names such as neg x instead of -:x.
If you look closely at it, there's not much there - it's actually easy to understand - defines a variant struct and an bunch of accessors to the different types within the embedded union. He prefers short names, and finally years later, java recommends short variable names for lambdas too!