In case anybody else is curious, since the workarounds are only offered for Linux and NetBSD, I was able to fix this on FreeBSD with:

    sudo certctl untrust /usr/share/certs/trusted/emSign_ECC_Root_CA_-_G3.pem

And on OpenBSD by editing /etc/ssl/cert.pem, removing everything starting from the line:

    === /C=IN/OU=emSign PKI/O=eMudhra Technologies Limited/CN=emSign ECC Root CA - G3

Up to but not including this line:

    === /C=IN/OU=emSign PKI/O=eMudhra Technologies Limited/CN=emSign Root CA - G1