How to add selfsigned certificate to bundle in git-bash?

Attempting to update git on a windows machine in git-bash with git update-git-for-windows fails with a message from curl:

curl: (60) SSL certificate problem: self signed certificate in certificate chainMore details here: https://curl.se/docs/sslcerts.htmlcurl failed to verify the legitimacy of the server and therefore could notestablish a secure connection to it. To learn more about this situation andhow to fix it, please visit the web page mentioned above.

I expected this problem, since we use self-signed certificates. I know it's no good, but I can't change it.

So where would I find the certificate bundle used by curl or git and add my own trusted root-certificate to it?