Function channel_peer_group_key 

pub fn channel_peer_group_key(
    config: &Config,
    channel_type: &str,
    alias: &str,
) -> Option<String>

The peer_groups key that holds bindings for <channel_type>.<alias>, or None when no group carries that ref yet.

For reporting where a binding lives. The writer selects its target by the group’s channel field, so the conventional <type>_<alias> name is a guess that may name nothing at all.