Mounting a plugin secret engine via API

here is an example of how to mount a secret engine using a plugin:

vault secrets enable -path=github -plugin-name=vault-plugin-secrets-github plugin

when calling this operation via API what is the plugin-name parameter translated to?

The documentation does not seem to mention it (/sys/mounts - HTTP API | Vault by HashiCorp).
The -output-curl-string parameter does not seem to work for this command.
So I having hard time figuring out what plugin-name is translated to, plugin_name maybe?

Seems plausible. I’ve never used it before but I did find reference to plugin_name in the plugins code: vault/backend.go at main · hashicorp/vault · GitHub as well as the mount code: vault/mount.go at main · hashicorp/vault · GitHub

Normally I’m able to find more explicit references. It’s worth a try and I’d be curious to see what you find out.