Function is_edge_name 

pub fn is_edge_name(context: &str) -> bool

I2 (#1971): whether context is a name an edge key can be derived from: dot-separated segments, each a lowercase letter, then lowercase letters and digits, with single underscores between runs of them (shop.orders, a_b.c2). On that domain edge_suffix is injective, which is what keeps one caller’s key from verifying another’s name.