Since the /var referred to here is the directory used by rpki-client which can't be overridden by anything in ports, imho it should just use /var not VARBASE.
(Similar case to ports which refers to /etc files which are part of the base system, which should be /etc not SYSCONFDIR). Index: Makefile =================================================================== RCS file: /cvs/ports/net/stayrtr/Makefile,v retrieving revision 1.1.1.1 diff -u -p -r1.1.1.1 Makefile --- Makefile 26 Jan 2023 13:38:49 -0000 1.1.1.1 +++ Makefile 26 Jan 2023 13:45:15 -0000 @@ -2,6 +2,7 @@ COMMENT= RPKI-To-Router implementation i MODGO_MODNAME= github.com/bgp/stayrtr MODGO_VERSION= v0.4.0 +REVISION= 0 DISTNAME= stayrtr-${MODGO_VERSION} @@ -10,8 +11,6 @@ HOMEPAGE= https://www.github.com/bgp/sta # BSD 3-Clause PERMIT_PACKAGE= yes - -SUBST_VARS= VARBASE MODULES= lang/go Index: pkg/README =================================================================== RCS file: /cvs/ports/net/stayrtr/pkg/README,v retrieving revision 1.1.1.1 diff -u -p -r1.1.1.1 README --- pkg/README 26 Jan 2023 13:38:49 -0000 1.1.1.1 +++ pkg/README 26 Jan 2023 13:45:15 -0000 @@ -8,4 +8,4 @@ To use your local RPKI cache, add to the And run: - # rcctl set stayrtr flags -cache ${VARBASE}/db/rpki-client/json + # rcctl set stayrtr flags -cache /var/db/rpki-client/json