Xdebug

Xdebug is an extension for PHP, and provides a range of features to improve the PHP development experience.

Xdebug’s most celebrated feature is its step debugger: it allows for pausing PHP execution mid-run and inspect what’s happening, with integration with IDE.

Documentation

See also Debugging PHP with VSCode and XDebug: A Step-by-Step Guide.

Related : Framework, Debug, PHP Editor, Integrated Environment of Development (IDE), Trace, Troubleshoot