Constant SHELL_CHANNEL_FORMAT_VERSION 

pub const SHELL_CHANNEL_FORMAT_VERSION: u32 = 1;

The format of a ShellChannelTable file this build reads and writes.

It versions only the wrapper (shell identity, binding energy, binding provenance); the wrapped CrossSectionTable keeps its own CACHE_FORMAT_VERSION, which this type does not change. Bump it whenever the meaning or layout of the wrapper changes.