The installer includes wintun MSM version 0.6, wrapped into MSI according to msi-example doc.
To use wintun driver instead of tap-window6, add "windows-driver wintun" to your VPN profile.
Please be aware that openvpn wintun support has not been yet reviewed and merged, so it may contain bugs.
Some performance numbers (with recent -O2 fix to windows build system):
Server - openvpn 2.4.4
tap-windows6: 390Mbit/s
wintun: 730Mbit/s
Server - openvpn3 with kernel acceleration
tap-windows6: 405Mbit/s
wintun: 1.05Gbit/s