The lost_source_maps.zip file you have requested: Maps Levels Missions / Map Packs / lost_source_maps.zip - 3.38mb is not available. Perhaps try browsing all files for the game Half-Life and upload any files you want to share or are missing. This is the only information we could locate:
This pack contains various source maps (*.rmf) for Half-Life 1 made by Jan Ripper (www.jan-ripper.de). A collection of unfinished source (*.rmf) maps for Half-Life 1.