- build.cfg: FREEBSD_VERSION -> ${FREEBSD_VERSION:-15.1-RELEASE}. The memstick
URL, checksum URL, cache path, and build-manifest all derive from it, so the
live-USB build bumps from this one line. The :- form also lets an operator
override at build time (FREEBSD_VERSION=15.2-RELEASE ./build.sh) without
editing git — previously a plain assignment clobbered any env value.
- docs: de-version README/BUILD/REQUIREMENTS + iso-build skill from '15.0' to
'15.x' so they stop drifting on every point release.
Verified: default derives the 15.1 memstick URL (HTTP 200, dated 12.jun.2026);
env override cascades to 15.2. ABI stays FreeBSD:15:amd64 (same major — no
package rebuild needed). build-vps.sh (mfsbsd) and poudriere keep their own
version knobs and are intentionally untouched (ABI-compatible, separate paths).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
