The "Hoodlum" modification is likely a fan-made patch or hack that alters the game's behavior, potentially adding new features, cars, or levels. However, I couldn't find specific information on what the "Hoodlum" mod entails, as it might be a lesser-known or obscure modification.
For NFSU2, Hoodlum released two major cracks: nfs underground 2 1.2 no cd hoodlum
The most popular way to play NFSU2 today is via the "Widescreen Fix." This community-made patch allows the game to run on 1080p, 1440p, and 4K monitors, fixing the stretched graphics of the 2004 release. This patch often includes its own No-CD functionality or requires a specific binary that supersedes the old HOODLUM file. The "Hoodlum" modification is likely a fan-made patch