eMudhra was a root CA. Their roots and intermediates were cross-signed by Sectigo since it was a new(-ish) root CA (a comment on Reddit characterized eMudhra as a Sectigo reseller, but I can't find verification of that), but I don't know to what extent that was done as a result of Sectigo's own evaluation vs. some internal process of a larger entity like the CA/Browser Forum. (Without cross-signing, it's difficult for a new CA to operate, so I imagine there must be some process by which a particular existing-CA cat is belled to be the cross-signer.)