Function build_info 

pub fn build_info() -> &'static [(&'static str, String)]

Which AgentMux a pane runs in, set on every process a pane starts so an agent can say so without reading it out of a log path:

• AGENTMUX_VERSION: the release version (0.59.16). The shell helpers also use it to name log pointer files, so it stays the plain version.
• AGENTMUX_BUILD: the exact build: a local portable’s label (0.59.16+g2a5424fe2.20261008T234046.81801), else the version.
• AGENTMUX_INSTANCE_CHANNEL: the channel this instance runs in (stable, or a local build’s own channel). Information only: AGENTMUX_CHANNEL, which says where an instance keeps its data, never reaches a pane, and nothing reads this one to choose a data directory.