This repository contains the source code for RePo, a floating-point debugging system built on top of the wasm3 WebAssembly runtime. RePo adds accurate residue tracking and selective re-execution to help diagnose floating-point errors and compare executions against higher-precision references. The repository includes the runtime implementation, supporting libraries, benchmark programs, and evaluation scripts used in the paper Accurate Residues for Floating-Point Debugging, accepted to OOPSLA'26.