A heatmap diff viewer has been developed for code reviews, designed to help identify which lines of code deserve more attention. Unlike standard review bots that primarily flag bugs, this tool assesses whether a line is worth a second look. It highlights issues like hard-coded secrets, unusual cryptographic modes, or complex logic that might be challenging for reviewers. To use the heatmap, simply replace "github.com" with "0github.com" in any GitHub pull request URL. The system works by cloning the repository into a virtual machine and utilizing gpt-5-codex to analyze each diff. This process generates a JSON data structure, which is then transformed into a color-coded heatmap indicating the level of attention each line requires. The heatmap itself is open source, allowing others to contribute or modify the tool as needed.