I stopped nginx-mainline.service and I was unable to restart it later due to the unit not being found.
Sure enough, the file does not exist any more in /usr/lib/systemd/system
I checked the bundle was still installed and ran swupd repair. I also tried removing and re-adding the bundle. That did not help either. It appears the file is no longer present in the package!
That was a mistake as the nginx-mainline content is being removed (to be replaced by nginx as we aren’t going to be providing both going forward). The bundle should have installed nginx as a replacement but did not and I have pushed a change out to make that happen for folks in the next release.
OK, I uninstalled nginx-mainline and installed nginx. Unfortunately it is missing two modules I was using, gzip_static and fancyindex, but I can do without.