I'm working on the reproducible-builds project [0] the noweb package uses icont to create several executables in /usr/bin and /usr/lib/noweb. Those executables appear to have some variance depending on the build environment. The differences show up consistently between octets 0x130 and 0x230. You can see them here: https://reproducible.debian.net/dbd/unstable/amd64/noweb_2.11b-9.debbindiff.html I'm not sure what the variance comes from (timestamps? something else?), but these file are generated with icont from files in src/icon/ You can see the build log here: https://reproducible.debian.net/rbuild/unstable/amd64/noweb_2.11b-9.rbuild.log does icon have a deterministic mode that can be used for noweb?