Sandboxfs was only ever experimental in Bazel and was fully removed in Bazel-7. Bazel was removed from Gentoo in Feb, but this was missed. Removal in 30 days. Reproducible: Always
Masked in https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=f56242c911f110c3d7607ab5856544e1e2a86aed