Not sure if this counts to you, but I believe FreeBSD still ships with functioning mail out of the box, and they use sendmail. On FreeBSD 12 at least, sudo actually reports incidents to root's mailbox :)
With that said, when I was engaged with the FreeBSD community years ago, there would be periodic bursts of drama over "debloating" the base install, and sendmail was one (of several) programs people wanted to remove in order to "debloat" the base install. So I wouldn't be surprised if the latest version no longer has functioning mail, let alone sendmail installed.
Not sure if this counts to you, but I believe FreeBSD still ships with functioning mail out of the box, and they use sendmail. On FreeBSD 12 at least, sudo actually reports incidents to root's mailbox :)
With that said, when I was engaged with the FreeBSD community years ago, there would be periodic bursts of drama over "debloating" the base install, and sendmail was one (of several) programs people wanted to remove in order to "debloat" the base install. So I wouldn't be surprised if the latest version no longer has functioning mail, let alone sendmail installed.