The document proposes a browser extension that uses multiple sequence alignment and content matching to detect and remove duplicate URLs (DUST). It discusses how existing methods have limitations and proposes a new method using multiple sequence alignment to generate normalization rules from URL clusters in an efficient manner. The system works by tokenizing URLs, clustering similar URLs, generating pairwise rules from clusters, and using Levenshtein distance and content matching to identify and remove duplicate URLs. The goal is to improve search engine performance and recommendation systems by removing redundant web content.