Within a high level design there's often a lot of room for variations in the implementation such as code structure; though this freedom decreases significantly if you have a wide enough audience to need to consider Hyrum's Law.
Concretely, let's say I'm designing a term-rewriting system. The program will be inspecting an abstract syntax tree (AST) for certain patterns, and if it detects those patterns, rewriting them. (e.g. if we see the AST for "1 + 1" rewrite to "2"). I might write up a document on the architecture for the system, and a list of rewriting rules I need. How those rules are written can be left up to individuals on my team as long as it fits into the architecture, has the required functionality, and is of reasonable quality.
Concretely, let's say I'm designing a term-rewriting system. The program will be inspecting an abstract syntax tree (AST) for certain patterns, and if it detects those patterns, rewriting them. (e.g. if we see the AST for "1 + 1" rewrite to "2"). I might write up a document on the architecture for the system, and a list of rewriting rules I need. How those rules are written can be left up to individuals on my team as long as it fits into the architecture, has the required functionality, and is of reasonable quality.