That's for a ro image with tmpmfs and varmfs[0], a minimal kernel, base and the packages nginx-lite, jansson, re2, curl, acme.sh and some services.
The system boots from an ISO into running nginx and hosting a basic network scanner[1] at a VPS provider.
I basically built from source with a custom SRCCONF[2], KERNCONF[3] and some other cleanup[4].
There may be easier ways to do it but it worked out pretty well for me.
[0] https://www.freebsd.org/cgi/man.cgi?rc.conf(5) [1] https://disco1.sajber.se/ [2] https://github.com/sebcat/yans/blob/master/tools/freebsd/vm/... [3] https://github.com/sebcat/yans/blob/master/tools/freebsd/vm/... [4] https://github.com/sebcat/yans/blob/master/tools/freebsd/vm/...