The portions of the SDLC that happen after the core code of a system is written can still have significant impacts on the development cycle. Historically, they might not involve a lot of real development effort—some code may be written as a one-off for various specific purposes such as packaging the system's code, or facilitating its installation on a target environment, for example. If the structure of the system's code base or, rarely, the language that the system is written in doesn't somehow prevent it, most of any code that was written in support of post-development activities would probably be created very early on in the development process in order to meet some other need.
As a case in point, packaging the code-base, and/or the creation of some installation mechanism is pretty likely to be undertaken the...