There’s a long list of tools that follow a general pattern: they take an input file and produce an output file, but the output file doesn’t just depend on the c

There’s a long list of tools that follow a general pattern: they take an input file and produce an output file, but the output file doesn’t just depend on the contents of the input file; it also embeds its modification time somewhere. Sometimes the goal is to be able to automatically regenerate the output if the input changes, by comparing timestamps. Sometimes it’s just intended as general-purpose metadata. Debian’s reproducible builds wiki page has many examples: https://wiki.debian.org/ReproducibleBuilds/Howto#Files_in_data.tar_contain_timestamps https://wiki.debian.org/ReproducibleBuilds/Howto#Files_in_da... Notably, this affects archivers such as tar and zip, but there’s also a long tail of application-specific tools.