Also note, Syd has been used as Exherbo's default sandbox for 16 years now and Exherbo is a source-based distribution which enables package testing by default (we call them "build_options: recommended_tests"), and every package build/test failure that happens under sandbox but not without sandbox is considered a sydbox bug. We have fixed a lot over the years. Moreover, we have a CI task to run a random selection of a hundred gnulib tests (under 64-bit and 32-bit respectively, x86-64, x86, armv{8..7}) on each push. We can therefore proudly say that Syd is reliable when it comes to functional correctness.