Replication package for: Requirement Verification Fragility: Measuring the Gap between Structural Traceability Coverage and Mutation-Validated Verification

Data, code, and pinned environment for the article "Requirement Verification Fragility: Measuring the Gap between Structural Traceability Coverage and Mutation-Validated Verification" (submitted to Empirical Software Engineering). The package contains: the structural constructs (fragility, essential tests, exact minimum requirement cover, redundancy) of three public gold requirement-to-test datasets (EasyClinic, EBT, AgileOERP); per-scenario coverage and full per-mutant, per-scenario kill matrices for the font and run modules of python-docx (v1.2.0; 37 requirements, 136 mutants, two equivalent deletions excluded at analysis), with the derived outcomes, threshold sweep, surviving-mutant inventory, feature-level (strict vs. union) layer, and negative controls; per-test coverage and first-killer mutation status for the Entry module of jrnl (17 requirements, 132 mutants), both for a seeded 80-scenario sample and for the full census of covering scenarios; the PIT 1.7.6 report and per-method outcomes for epubcheck's OPFHandler (18 methods, 155 mutants). All Python harness scripts are included. A single script, run_all.sh, regenerates every derived file from public sources at pinned commits. Data and documentation are released under CC BY 4.0 and code under MIT.