Time zone rule propagation: code, protocol and records

Code, study protocol, curated records, and generated figures and tables of a study of how time zone rule changes reach backend software. For 41 rule changes of the IANA time zone database released over ten years, the records give, for every maintained release line of 21 components (distribution packages, language runtimes and libraries, database servers, and official container images), when the line made the change available and whether that happened before the change took effect. The package contains the event, cell, adoption and validation records, the analysis code with the event-cluster bootstrap, and executable checks. Running python checks/reproduce.py recomputes the derived records, figures and tables from the shipped records and compares them with the shipped files; README.md gives the requirements and options. Third-party source bodies, release archives, package files and container layers are not redistributed; the records keep their source URLs and object identifiers.