three is also NetworkManager-libreswan which would be for LibreSwan - have the two modules been merged by upstream?

NetworkManager-libreswan is compatible with libreswan and openswan, but not strongswan. Before version 1.2, it was known as NetworkManager-openswan. At runtime /usr/sbin/ipsec --version is used to determine which one is being used, although the logic it uses is a bit screwed up in places in the code, as it assumes if it is not openswan, it can only be libreswan.

NetworkManager-l2tp is compatible with strongswan and libreswan, at runtime /usr/sbin/ipsec --version is used to determine which one is being used.

NetworkManager-libreswan provides IPsec (IKEv1) + XAUTH VPN as well as newer IPsec (IKEv2) VPN.

NetworkManager-l2tp provides L2TP VPN with optional IPsec tunneling.

strongswan and libreswan definitely have not been merged upstream.

It is odd that openSUSE provides NetworkManager-libreswan, but no libreswan package, which someone has commented on the following page : https://build.opensuse.org/package/show/openSUSE:Factory/NetworkManager-libreswan

As some openSUSE NetworkManager-l2tp users weren't able to connect to their workplace using strongswan, but were with libreswan, I made a libreswan package : https://build.opensuse.org/package/show/home:dkosovic/libreswan

Last year I didn't have any luck with trying to submit an earlier version of a libreswan package and didn't bother trying with later versions.

@dimstar, @factory-repo-checker, @sreeves1: review reminder