In the materials directory of the Half-Life 2 leak, there is a standalone .txt file named oldtrans.txt, and in this file lies what seems to be a vast assortment of material naming transitions from what can be hypothesized to be an older era of development- hence the name, "oldtrans". This text provided has proven more than useful to the community of leak mappers wanting to implement proper texture fixes/replacements to many older maps present in the WC mappack.