pub static SUPPORTED_SIG_ALGS: WebPkiSupportedAlgorithmsExpand description
Signature verification algorithms, for certificate chains and for the
handshake.
all is what certificate chains are verified with, and mapping is what
the handshake signature is looked up in. Both are needed: a chain signed
with PKCS#1 v1.5 can carry a key that then signs the handshake with PSS, and
TLS 1.3 requires exactly that combination.