Certificate chain
During the TLS handshake the server presents a leaf certificate and usually intermediate CA certificates. Clients build a path to a locally trusted root. TLSWatch reports the presented chain as seen by Node’s TLS stack.
Chain depth
Depth is counted from the leaf at depth 0 through linked issuer certificates. A depth of 1 often means only a leaf was linked; depth ≥ 2 usually means intermediates were presented.
Self-signed / single-node
If the leaf’s issuer equals its subject (or the issuer link points to itself), TLSWatch sets a self-signed / single-node flag. That is common for lab certs and some internal services — educational signal only.
Trust-store note
Whether this runtime accepts the chain against its platform trust store is shown as informational. Different clients (browsers, mobile OS, custom trust stores) can disagree. A trust-store accept must never be read as a risk clearance for the site.