The npm package 'postcss-minify-selector' is a malicious typosquat designed to mimic the legitimate 'postcss-minify-selectors' plugin. It includes a dependency on another similarly named typosquat package and executes side-effect code upon being required, which can lead to full system compromise. Any system with this package installed or running should be considered fully compromised, and all secrets and keys must be rotated. Removal of the package alone may not eliminate the malicious presence.